SPARK-1902 Silence stacktrace from logs when doing port failover to port n+1

Before:

```
14/06/08 23:58:23 WARN AbstractLifeCycle: FAILED SelectChannelConnector@0.0.0.0:4040: java.net.BindException: Address already in use
java.net.BindException: Address already in use
	at sun.nio.ch.Net.bind0(Native Method)
	at sun.nio.ch.Net.bind(Net.java:444)
	at sun.nio.ch.Net.bind(Net.java:436)
	at sun.nio.ch.ServerSocketChannelImpl.bind(ServerSocketChannelImpl.java:214)
	at sun.nio.ch.ServerSocketAdaptor.bind(ServerSocketAdaptor.java:74)
	at org.eclipse.jetty.server.nio.SelectChannelConnector.open(SelectChannelConnector.java:187)
	at org.eclipse.jetty.server.AbstractConnector.doStart(AbstractConnector.java:316)
	at org.eclipse.jetty.server.nio.SelectChannelConnector.doStart(SelectChannelConnector.java:265)
	at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:64)
	at org.eclipse.jetty.server.Server.doStart(Server.java:293)
	at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:64)
	at org.apache.spark.ui.JettyUtils$$anonfun$1.apply$mcV$sp(JettyUtils.scala:192)
	at org.apache.spark.ui.JettyUtils$$anonfun$1.apply(JettyUtils.scala:192)
	at org.apache.spark.ui.JettyUtils$$anonfun$1.apply(JettyUtils.scala:192)
	at scala.util.Try$.apply(Try.scala:161)
	at org.apache.spark.ui.JettyUtils$.connect$1(JettyUtils.scala:191)
	at org.apache.spark.ui.JettyUtils$.startJettyServer(JettyUtils.scala:205)
	at org.apache.spark.ui.WebUI.bind(WebUI.scala:99)
	at org.apache.spark.SparkContext.<init>(SparkContext.scala:223)
	at org.apache.spark.repl.SparkILoop.createSparkContext(SparkILoop.scala:957)
	at $line3.$read$$iwC$$iwC.<init>(<console>:8)
	at $line3.$read$$iwC.<init>(<console>:14)
	at $line3.$read.<init>(<console>:16)
	at $line3.$read$.<init>(<console>:20)
	at $line3.$read$.<clinit>(<console>)
	at $line3.$eval$.<init>(<console>:7)
	at $line3.$eval$.<clinit>(<console>)
	at $line3.$eval.$print(<console>)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:606)
	at org.apache.spark.repl.SparkIMain$ReadEvalPrint.call(SparkIMain.scala:788)
	at org.apache.spark.repl.SparkIMain$Request.loadAndRun(SparkIMain.scala:1056)
	at org.apache.spark.repl.SparkIMain.loadAndRunReq$1(SparkIMain.scala:614)
	at org.apache.spark.repl.SparkIMain.interpret(SparkIMain.scala:645)
	at org.apache.spark.repl.SparkIMain.interpret(SparkIMain.scala:609)
	at org.apache.spark.repl.SparkILoop.reallyInterpret$1(SparkILoop.scala:796)
	at org.apache.spark.repl.SparkILoop.interpretStartingWith(SparkILoop.scala:841)
	at org.apache.spark.repl.SparkILoop.command(SparkILoop.scala:753)
	at org.apache.spark.repl.SparkILoopInit$$anonfun$initializeSpark$1.apply(SparkILoopInit.scala:121)
	at org.apache.spark.repl.SparkILoopInit$$anonfun$initializeSpark$1.apply(SparkILoopInit.scala:120)
	at org.apache.spark.repl.SparkIMain.beQuietDuring(SparkIMain.scala:263)
	at org.apache.spark.repl.SparkILoopInit$class.initializeSpark(SparkILoopInit.scala:120)
	at org.apache.spark.repl.SparkILoop.initializeSpark(SparkILoop.scala:56)
	at org.apache.spark.repl.SparkILoop$$anonfun$process$1$$anonfun$apply$mcZ$sp$5.apply$mcV$sp(SparkILoop.scala:913)
	at org.apache.spark.repl.SparkILoopInit$class.runThunks(SparkILoopInit.scala:142)
	at org.apache.spark.repl.SparkILoop.runThunks(SparkILoop.scala:56)
	at org.apache.spark.repl.SparkILoopInit$class.postInitialization(SparkILoopInit.scala:104)
	at org.apache.spark.repl.SparkILoop.postInitialization(SparkILoop.scala:56)
	at org.apache.spark.repl.SparkILoop$$anonfun$process$1.apply$mcZ$sp(SparkILoop.scala:930)
	at org.apache.spark.repl.SparkILoop$$anonfun$process$1.apply(SparkILoop.scala:884)
	at org.apache.spark.repl.SparkILoop$$anonfun$process$1.apply(SparkILoop.scala:884)
	at scala.tools.nsc.util.ScalaClassLoader$.savingContextLoader(ScalaClassLoader.scala:135)
	at org.apache.spark.repl.SparkILoop.process(SparkILoop.scala:884)
	at org.apache.spark.repl.SparkILoop.process(SparkILoop.scala:982)
	at org.apache.spark.repl.Main$.main(Main.scala:31)
	at org.apache.spark.repl.Main.main(Main.scala)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:606)
	at org.apache.spark.deploy.SparkSubmit$.launch(SparkSubmit.scala:292)
	at org.apache.spark.deploy.SparkSubmit$.main(SparkSubmit.scala:55)
	at org.apache.spark.deploy.SparkSubmit.main(SparkSubmit.scala)
14/06/08 23:58:23 WARN AbstractLifeCycle: FAILED org.eclipse.jetty.server.Server@7439e55a: java.net.BindException: Address already in use
java.net.BindException: Address already in use
	at sun.nio.ch.Net.bind0(Native Method)
	at sun.nio.ch.Net.bind(Net.java:444)
	at sun.nio.ch.Net.bind(Net.java:436)
	at sun.nio.ch.ServerSocketChannelImpl.bind(ServerSocketChannelImpl.java:214)
	at sun.nio.ch.ServerSocketAdaptor.bind(ServerSocketAdaptor.java:74)
	at org.eclipse.jetty.server.nio.SelectChannelConnector.open(SelectChannelConnector.java:187)
	at org.eclipse.jetty.server.AbstractConnector.doStart(AbstractConnector.java:316)
	at org.eclipse.jetty.server.nio.SelectChannelConnector.doStart(SelectChannelConnector.java:265)
	at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:64)
	at org.eclipse.jetty.server.Server.doStart(Server.java:293)
	at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:64)
	at org.apache.spark.ui.JettyUtils$$anonfun$1.apply$mcV$sp(JettyUtils.scala:192)
	at org.apache.spark.ui.JettyUtils$$anonfun$1.apply(JettyUtils.scala:192)
	at org.apache.spark.ui.JettyUtils$$anonfun$1.apply(JettyUtils.scala:192)
	at scala.util.Try$.apply(Try.scala:161)
	at org.apache.spark.ui.JettyUtils$.connect$1(JettyUtils.scala:191)
	at org.apache.spark.ui.JettyUtils$.startJettyServer(JettyUtils.scala:205)
	at org.apache.spark.ui.WebUI.bind(WebUI.scala:99)
	at org.apache.spark.SparkContext.<init>(SparkContext.scala:223)
	at org.apache.spark.repl.SparkILoop.createSparkContext(SparkILoop.scala:957)
	at $line3.$read$$iwC$$iwC.<init>(<console>:8)
	at $line3.$read$$iwC.<init>(<console>:14)
	at $line3.$read.<init>(<console>:16)
	at $line3.$read$.<init>(<console>:20)
	at $line3.$read$.<clinit>(<console>)
	at $line3.$eval$.<init>(<console>:7)
	at $line3.$eval$.<clinit>(<console>)
	at $line3.$eval.$print(<console>)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:606)
	at org.apache.spark.repl.SparkIMain$ReadEvalPrint.call(SparkIMain.scala:788)
	at org.apache.spark.repl.SparkIMain$Request.loadAndRun(SparkIMain.scala:1056)
	at org.apache.spark.repl.SparkIMain.loadAndRunReq$1(SparkIMain.scala:614)
	at org.apache.spark.repl.SparkIMain.interpret(SparkIMain.scala:645)
	at org.apache.spark.repl.SparkIMain.interpret(SparkIMain.scala:609)
	at org.apache.spark.repl.SparkILoop.reallyInterpret$1(SparkILoop.scala:796)
	at org.apache.spark.repl.SparkILoop.interpretStartingWith(SparkILoop.scala:841)
	at org.apache.spark.repl.SparkILoop.command(SparkILoop.scala:753)
	at org.apache.spark.repl.SparkILoopInit$$anonfun$initializeSpark$1.apply(SparkILoopInit.scala:121)
	at org.apache.spark.repl.SparkILoopInit$$anonfun$initializeSpark$1.apply(SparkILoopInit.scala:120)
	at org.apache.spark.repl.SparkIMain.beQuietDuring(SparkIMain.scala:263)
	at org.apache.spark.repl.SparkILoopInit$class.initializeSpark(SparkILoopInit.scala:120)
	at org.apache.spark.repl.SparkILoop.initializeSpark(SparkILoop.scala:56)
	at org.apache.spark.repl.SparkILoop$$anonfun$process$1$$anonfun$apply$mcZ$sp$5.apply$mcV$sp(SparkILoop.scala:913)
	at org.apache.spark.repl.SparkILoopInit$class.runThunks(SparkILoopInit.scala:142)
	at org.apache.spark.repl.SparkILoop.runThunks(SparkILoop.scala:56)
	at org.apache.spark.repl.SparkILoopInit$class.postInitialization(SparkILoopInit.scala:104)
	at org.apache.spark.repl.SparkILoop.postInitialization(SparkILoop.scala:56)
	at org.apache.spark.repl.SparkILoop$$anonfun$process$1.apply$mcZ$sp(SparkILoop.scala:930)
	at org.apache.spark.repl.SparkILoop$$anonfun$process$1.apply(SparkILoop.scala:884)
	at org.apache.spark.repl.SparkILoop$$anonfun$process$1.apply(SparkILoop.scala:884)
	at scala.tools.nsc.util.ScalaClassLoader$.savingContextLoader(ScalaClassLoader.scala:135)
	at org.apache.spark.repl.SparkILoop.process(SparkILoop.scala:884)
	at org.apache.spark.repl.SparkILoop.process(SparkILoop.scala:982)
	at org.apache.spark.repl.Main$.main(Main.scala:31)
	at org.apache.spark.repl.Main.main(Main.scala)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:606)
	at org.apache.spark.deploy.SparkSubmit$.launch(SparkSubmit.scala:292)
	at org.apache.spark.deploy.SparkSubmit$.main(SparkSubmit.scala:55)
	at org.apache.spark.deploy.SparkSubmit.main(SparkSubmit.scala)
14/06/08 23:58:23 INFO JettyUtils: Failed to create UI at port, 4040. Trying again.
14/06/08 23:58:23 INFO JettyUtils: Error was: Failure(java.net.BindException: Address already in use)
14/06/08 23:58:23 INFO SparkUI: Started SparkUI at http://aash-mbp.local:4041
````

After:
```
14/06/09 00:04:12 INFO JettyUtils: Failed to create UI at port, 4040. Trying again.
14/06/09 00:04:12 INFO JettyUtils: Error was: Failure(java.net.BindException: Address already in use)
14/06/09 00:04:12 INFO Server: jetty-8.y.z-SNAPSHOT
14/06/09 00:04:12 INFO AbstractConnector: Started SelectChannelConnector@0.0.0.0:4041
14/06/09 00:04:12 INFO SparkUI: Started SparkUI at http://aash-mbp.local:4041
```

Lengthy logging comes from this line of code in Jetty: http://grepcode.com/file/repo1.maven.org/maven2/org.eclipse.jetty.aggregate/jetty-all/9.1.3.v20140225/org/eclipse/jetty/util/component/AbstractLifeCycle.java#210
That other line has been in spark since way before we added this port retrying, so I don't think that's why it's there. IIRC there are various jetty services that will spit out logging information, especially at start up and shut down, and so we've always used this blanket statement. See for example Spark 0.5 which is more than 2 years old (before we even had a UI).

https://github.com/apache/spark/blob/branch-0.5/conf/log4j.properties.template#L7

If you'd like to audit this at some point that would be great (it might be hard to find all cases where jetty will print something). But since this change is about the port issue specifically, it might be good not to change that other behavior in this patch