SPARK-1450 [EC2] Specify the default zone in the EC2 script help

This looks like a one-liner, so I took a shot at it. There can be no fixed default availability zone since the names are different per region. But the default behavior can be documented:

```
    if opts.zone == "":
        opts.zone = random.choice(conn.get_all_zones()).name
```

Author: Sean Owen <sowen@cloudera.com>

Closes #3454 from srowen/SPARK-1450 and squashes the following commits:

9193cf3 [Sean Owen] Document that --zone defaults to a single random zone
[SPARK-4597] Use proper exception and reset variable in Utils.createTempDir()

`File.exists()` and `File.mkdirs()` only throw `SecurityException` instead of `IOException`. Then, when an exception is thrown, `dir` should be reset too.

Author: Liang-Chi Hsieh <viirya@gmail.com>

Closes #3449 from viirya/fix_createtempdir and squashes the following commits:

36cacbd [Liang-Chi Hsieh] Use proper exception and reset variable.
MAINTENANCE: Automated closing of pull requests.

This commit exists to close the following pull requests on Github:

Closes #3451 (close requested by 'pwendell')
Closes #1310 (close requested by 'pwendell')
Closes #3207 (close requested by 'JoshRosen')
[SPARK-3398] [SPARK-4325] [EC2] Use EC2 status checks.

This PR re-introduces [0e648bc](https://github.com/apache/spark/commit/0e648bc2bedcbeb55fce5efac04f6dbad9f063b4) from PR #2339, which somehow never made it into the codebase.

Additionally, it removes a now-unnecessary linear backoff on the SSH checks since we are blocking on EC2 status checks before testing SSH.

Author: Nicholas Chammas <nicholas.chammas@gmail.com>

Closes #3195 from nchammas/remove-ec2-ssh-backoff and squashes the following commits:

efb29e1 [Nicholas Chammas] Revert "Remove linear backoff."
ef3ca99 [Nicholas Chammas] reuse conn
adb4eaa [Nicholas Chammas] Remove linear backoff.
55caa24 [Nicholas Chammas] Check EC2 status checks before SSH.
Include the key name when failing on an invalid value.

Admittedly a really small tweak.

Author: Stephen Haberman <stephen@exigencecorp.com>

Closes #3514 from stephenh/include-key-name-in-npe and squashes the following commits:

937740a [Stephen Haberman] Include the key name when failing on an invalid value.
[SPARK-4057] Use -agentlib instead of -Xdebug in sbt-launch-lib.bash for debugging

In -launch-lib.bash, -Xdebug option is used for debugging. We should use -agentlib option for Java 6+.

Author: Kousuke Saruta <sarutak@oss.nttdata.co.jp>

Closes #2904 from sarutak/SPARK-4057 and squashes the following commits:

39b5320 [Kousuke Saruta] Merge branch 'master' of git://git.apache.org/spark into SPARK-4057
26b4af8 [Kousuke Saruta] Improved java option for debugging
[SPARK-4505][Core] Add a ClassTag parameter to CompactBuffer[T]

Added a ClassTag parameter to CompactBuffer. So CompactBuffer[T] can create primitive arrays for primitive types. It will reduce the memory usage for primitive types significantly and only pay minor performance lost.

Here is my test code:
```Scala
  // Call org.apache.spark.util.SizeEstimator.estimate
  def estimateSize(obj: AnyRef): Long = {
    val c = Class.forName("org.apache.spark.util.SizeEstimator$")
    val f = c.getField("MODULE$")
    val o = f.get(c)
    val m = c.getMethod("estimate", classOf[Object])
    m.setAccessible(true)
    m.invoke(o, obj).asInstanceOf[Long]
  }

  sc.parallelize(1 to 10000).groupBy(_ => 1).foreach {
    case (k, v) =>
      println(v.getClass() + " size: " + estimateSize(v))
  }
```

Using the previous CompactBuffer outputed
```
class org.apache.spark.util.collection.CompactBuffer size: 313358
```

Using the new CompactBuffer outputed
```
class org.apache.spark.util.collection.CompactBuffer size: 65712
```

In this case, the new `CompactBuffer` only used 20% memory of the previous one. It's really helpful for `groupByKey` when using a primitive value.

Author: zsxwing <zsxwing@gmail.com>

Closes #3378 from zsxwing/SPARK-4505 and squashes the following commits:

4abdbba [zsxwing] Add a ClassTag parameter to reduce the memory usage of CompactBuffer[T] when T is a primitive type
SPARK-4507: PR merge script should support closing multiple JIRA tickets

This will fix SPARK-4507.

For pull requests that reference multiple JIRAs in their titles, it would be helpful if the PR merge script offered to close all of them.

Author: Takayuki Hasegawa <takayuki.hasegawa0311@gmail.com>

Closes #3428 from hase1031/SPARK-4507 and squashes the following commits:

bf6d64b [Takayuki Hasegawa] SPARK-4507: try to resolve issue when no JIRAs in title
401224c [Takayuki Hasegawa] SPARK-4507: moved codes as before
ce89021 [Takayuki Hasegawa] SPARK-4507: PR merge script should support closing multiple JIRA tickets
[DOCS][BUILD] Add instruction to use change-version-to-2.11.sh in 'Building for Scala 2.11'.

To build with Scala 2.11, we have to execute `change-version-to-2.11.sh` before Maven execute, otherwise inter-module dependencies are broken.

Author: Takuya UESHIN <ueshin@happy-camper.st>

Closes #3361 from ueshin/docs/building-spark_2.11 and squashes the following commits:

1d29126 [Takuya UESHIN] Add instruction to use change-version-to-2.11.sh in 'Building for Scala 2.11'.
SPARK-2143 [WEB UI] Add Spark version to UI footer

This PR adds the Spark version number to the UI footer; this is how it looks:

![screen shot 2014-11-21 at 22 58 40](https://cloud.githubusercontent.com/assets/822522/5157738/f4822094-7316-11e4-98f1-333a535fdcfa.png)

Author: Sean Owen <sowen@cloudera.com>

Closes #3410 from srowen/SPARK-2143 and squashes the following commits:

e9b3a7a [Sean Owen] Add Spark version to footer
[SPARK-4623]Add the some error infomation if using spark-sql in yarn-cluster mode

If using spark-sql in yarn-cluster mode, print an error infomation just as the spark shell in yarn-cluster mode.

Author: carlmartin <carlmartinmax@gmail.com>
Author: huangzhaowei <carlmartinmax@gmail.com>

Closes #3479 from SaintBacchus/sparkSqlShell and squashes the following commits:

35829a9 [carlmartin] improve the description of comment
e6c1eb7 [carlmartin] add a comment in bin/spark-sql to remind user who wants to change the class
f1c5c8d [carlmartin] Merge branch 'master' into sparkSqlShell
8e112c5 [huangzhaowei] singular form
ec957bc [carlmartin] Add the some error infomation if using spark-sql in yarn-cluster mode
7bcecc2 [carlmartin] Merge branch 'master' of https://github.com/apache/spark into codereview
4fad75a [carlmartin] Add the Error infomation using spark-sql in yarn-cluster mode
[SPARK-4656][Doc] Typo in Programming Guide markdown

Grammatical error in Programming Guide document

Author: lewuathe <lewuathe@me.com>

Closes #3412 from Lewuathe/typo-programming-guide and squashes the following commits:

a3e2f00 [lewuathe] Typo in Programming Guide markdown
[DOC] Fixes formatting typo in SQL programming guide

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Author: Cheng Lian <lian@databricks.com>

Closes #3498 from liancheng/fix-sql-doc-typo and squashes the following commits:

865ecd7 [Cheng Lian] Fixes formatting typo in SQL programming guide
MAINTENANCE: Automated closing of pull requests.

This commit exists to close the following pull requests on Github:

Closes #2915 (close requested by 'JoshRosen')
Closes #3140 (close requested by 'JoshRosen')
Closes #3366 (close requested by 'JoshRosen')
[SPARK-4632] version update

Author: Prabeesh K <prabsmails@gmail.com>

Closes #3495 from prabeesh/master and squashes the following commits:

ab03d50 [Prabeesh K] Update pom.xml
8c6437e [Prabeesh K] Revert
e10b40a [Prabeesh K] version update
dbac9eb [Prabeesh K] Revert
ec0b1c3 [Prabeesh K] [SPARK-4632] version update
a835505 [Prabeesh K] [SPARK-4632] version update
831391b [Prabeesh K]  [SPARK-4632] version update
Fix wrong file name pattern in .gitignore

In .gitignore, there is an entry for spark-*-bin.tar.gz but considering make-distribution.sh, the name pattern should be spark-*-bin-*.tgz.

This change is really small so I don't open issue in JIRA. If it's needed, please let me know.

Author: Kousuke Saruta <sarutak@oss.nttdata.co.jp>

Closes #3529 from sarutak/fix-wrong-tgz-pattern and squashes the following commits:

de3c70a [Kousuke Saruta] Fixed wrong file name pattern in .gitignore
SPARK-2192 [BUILD] Examples Data Not in Binary Distribution

Simply, add data/ to distributions. This adds about 291KB (compressed) to the tarball, FYI.

Author: Sean Owen <sowen@cloudera.com>

Closes #3480 from srowen/SPARK-2192 and squashes the following commits:

47688f1 [Sean Owen] Add data/ to distributions
[SPARK-4664][Core] Throw an exception when spark.akka.frameSize > 2047

If `spark.akka.frameSize` > 2047, it will overflow and become negative. Should have some assertion in `maxFrameSizeBytes` to warn people.

Author: zsxwing <zsxwing@gmail.com>

Closes #3527 from zsxwing/SPARK-4664 and squashes the following commits:

0089c7a [zsxwing] Throw an exception when spark.akka.frameSize > 2047
[SPARK-4661][Core] Minor code and docs cleanup

Author: zsxwing <zsxwing@gmail.com>

Closes #3521 from zsxwing/SPARK-4661 and squashes the following commits:

03cbe3f [zsxwing] Minor code and docs cleanup
Documentation: add description for repartitionAndSortWithinPartitions

Author: Madhu Siddalingaiah <madhu@madhu.com>

Closes #3390 from msiddalingaiah/master and squashes the following commits:

cbccbfe [Madhu Siddalingaiah] Documentation: replace <b> with <code> (again)
332f7a2 [Madhu Siddalingaiah] Documentation: replace <b> with <code>
cd2b05a [Madhu Siddalingaiah] Merge remote-tracking branch 'upstream/master'
0fc12d7 [Madhu Siddalingaiah] Documentation: add description for repartitionAndSortWithinPartitions