[Build] Diff from branch point

Sometimes Jenkins posts [spurious reports of new classes being added](https://github.com/apache/spark/pull/2339#issuecomment-56570170). I believe this stems from diffing the patch against `master`, as opposed to against `master...`, which starts from the commit the PR was branched from.

This patch fixes that behavior.

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

Closes #2512 from nchammas/diff-only-commits-ahead and squashes the following commits:

c065599 [Nicholas Chammas] comment typo fix
a453c67 [Nicholas Chammas] diff from branch point
[SPARK-3659] Set EC2 version to 1.1.0 and update version map

This brings the master branch in sync with branch-1.1

Author: Shivaram Venkataraman <shivaram@cs.berkeley.edu>

Closes #2510 from shivaram/spark-ec2-version and squashes the following commits:

bb0dd16 [Shivaram Venkataraman] Set EC2 version to 1.1.0 and update version map
[SPARK-3634] [PySpark] User's module should take precedence over system modules

Python modules added through addPyFile should take precedence over system modules.

This patch put the path for user added module in the front of sys.path (just after '').

Author: Davies Liu <davies.liu@gmail.com>

Closes #2492 from davies/path and squashes the following commits:

4a2af78 [Davies Liu] fix tests
f7ff4da [Davies Liu] ad license header
6b0002f [Davies Liu] add tests
c16c392 [Davies Liu] put addPyFile in front of sys.path
[SPARK-3679] [PySpark] pickle the exact globals of functions

function.func_code.co_names has all the names used in the function, including name of attributes. It will pickle some unnecessary globals if there is a global having the same name with attribute (in co_names).

There is a regression introduced by #2144, revert part of changes in that PR.

cc JoshRosen

Author: Davies Liu <davies.liu@gmail.com>

Closes #2522 from davies/globals and squashes the following commits:

dfbccf5 [Davies Liu] fix bug while pickle globals of function
[SPARK-3615][Streaming]Fix Kafka unit test hard coded Zookeeper port issue

Details can be seen in [SPARK-3615](https://issues.apache.org/jira/browse/SPARK-3615).

Author: jerryshao <saisai.shao@intel.com>

Closes #2483 from jerryshao/SPARK_3615 and squashes the following commits:

8555563 [jerryshao] Fix Kafka unit test hard coded Zookeeper port issue
[SPARK-546] Add full outer join to RDD and DStream.

leftOuterJoin and rightOuterJoin are already implemented.  This patch adds fullOuterJoin.

Author: Aaron Staple <aaron.staple@gmail.com>

Closes #1395 from staple/SPARK-546 and squashes the following commits:

1f5595c [Aaron Staple] Fix python style
7ac0aa9 [Aaron Staple] [SPARK-546] Add full outer join to RDD and DStream.
3b5d137 [Aaron Staple] In JavaPairDStream, make class tag specification in rightOuterJoin consistent with other functions.
31f2956 [Aaron Staple] Fix left outer join documentation comments.
[SPARK-2778] [yarn] Add yarn integration tests.

This patch adds a couple of, currently, very simple integration tests
to make sure both client and cluster modes are working. The tests don't
do much yet other than run a simple job, but the plan is to enhance
them after we get the framework in.

The cluster tests are noisy, so redirect all log output to a file
like other tests do. Copying the conf around sucks but it's less
work than messing with maven/sbt and having to clean up other
projects.

Note the test is only added for yarn-stable. The code compiles
against yarn-alpha but there are two issues I ran into that I
could not overcome:
- an old netty dependency kept creeping into the classpath and
  causing akka to not work, when using sbt; the old netty was
  correctly suppressed under maven.
- MiniYARNCluster kept failing to execute containers because it
  did not create the NM's local dir itself; this is apparently
  a known behavior, but I'm not sure how to work around it.

None of those issues are present with the stable Yarn.

Also, these tests are a little slow to run. Apparently Spark doesn't
yet tag tests (so that these could be isolated in a "slow" batch),
so this is something to keep in mind.

Author: Marcelo Vanzin <vanzin@cloudera.com>

Closes #2257 from vanzin/yarn-tests and squashes the following commits:

6d5b84e [Marcelo Vanzin] Fix wrong system property being set.
8b0933d [Marcelo Vanzin] Merge branch 'master' into yarn-tests
5c2b56f [Marcelo Vanzin] Use custom log4j conf for Yarn containers.
ec73f17 [Marcelo Vanzin] More review feedback.
67f5b02 [Marcelo Vanzin] Review feedback.
f01517c [Marcelo Vanzin] Review feedback.
68fbbbf [Marcelo Vanzin] Use older constructor available in older Hadoop releases.
d07ef9a [Marcelo Vanzin] Merge branch 'master' into yarn-tests
add8416 [Marcelo Vanzin] [SPARK-2778] [yarn] Add yarn integration tests.
Merge branch 'master' of git://git.apache.org/spark into yarn-scalastyle-modification