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
This might fail our style checks, should be `if (f.toString...`