Fix issue in ReplSuite with hadoop-provided profile.

When building the assembly with the maven "hadoop-provided"
profile, the executors were failing to come up because Hadoop classes
were not found in the classpath anymore; so add them explicitly to
the classpath using spark.executor.extraClassPath. This is only
needed for the local-cluster mode, but doesn't affect other tests,
so it's added for all of them to keep the code simpler.

Author: Marcelo Vanzin <vanzin@cloudera.com>

Closes #781 from vanzin/repl-test-fix and squashes the following commits:

4f0a3b0 [Marcelo Vanzin] Fix issue in ReplSuite with hadoop-provided profile.
[SPARK-2029] Bump pom.xml version number of master branch to 1.1.0-SNAPSHOT.

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

Closes #974 from ueshin/issues/SPARK-2029 and squashes the following commits:

e19e8f4 [Takuya UESHIN] Bump version number to 1.1.0-SNAPSHOT.
SPARK-1677: allow user to disable output dir existence checking

https://issues.apache.org/jira/browse/SPARK-1677

For compatibility with older versions of Spark it would be nice to have an option `spark.hadoop.validateOutputSpecs` (default true)  for the user to disable the output directory existence checking

Author: CodingCat <zhunansjtu@gmail.com>

Closes #947 from CodingCat/SPARK-1677 and squashes the following commits:

7930f83 [CodingCat] miao
c0c0e03 [CodingCat] bug fix and doc update
5318562 [CodingCat] bug fix
13219b5 [CodingCat] allow user to disable output dir existence checking
[SPARK-2036] [SQL] CaseConversionExpression should check if the evaluated value is null.

`CaseConversionExpression` should check if the evaluated value is `null`.

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

Closes #982 from ueshin/issues/SPARK-2036 and squashes the following commits:

61e1c54 [Takuya UESHIN] Add check if the evaluated value is null.
HOTFIX: Remove generated-mima-excludes file after runing MIMA.

This has been causing some false failures on PR's that don't merge
correctly.

Author: Patrick Wendell <pwendell@gmail.com>

Closes #971 from pwendell/mima and squashes the following commits:

1dc80aa [Patrick Wendell] HOTFIX: Remove generated-mima-excludes file after runing MIMA.
sbt 0.13.X should be using sbt-assembly 0.11.X

https://github.com/sbt/sbt-assembly/blob/master/README.md

Author: Kalpit Shah <shahkalpit84@gmail.com>

Closes #555 from kalpit/upgrade/sbtassembly and squashes the following commits:

1fa7324 [Kalpit Shah] sbt 0.13.X should be using sbt-assembly 0.11.X
Remove compile-scoped junit dependency.

This avoids having junit classes showing up in the assembly jar.
I verified that only test classes in the jtransforms package
use junit.

Author: Marcelo Vanzin <vanzin@cloudera.com>

Closes #794 from vanzin/junit-dep-exclusion and squashes the following commits:

274e1c2 [Marcelo Vanzin] Remove junit from assembly in sbt build also.
ad950be [Marcelo Vanzin] Remove compile-scoped junit dependency.
[SPARK-2041][SQL] Correctly analyze queries where columnName == tableName.

Author: Michael Armbrust <michael@databricks.com>

Closes #985 from marmbrus/tableName and squashes the following commits:

3caaa27 [Michael Armbrust] Correctly analyze queries where columnName == tableName.
Use pluggable clock in DAGSheduler #SPARK-2031

DAGScheduler supports pluggable clock like what TaskSetManager does.

Author: CrazyJvm <crazyjvm@gmail.com>

Closes #976 from CrazyJvm/clock and squashes the following commits:

6779a4c [CrazyJvm] Use pluggable clock in DAGSheduler
[SPARK-2025] Unpersist edges of previous graph in Pregel

Due to a bug introduced by apache/spark#497, Pregel does not unpersist replicated vertices from previous iterations. As a result, they stay cached until memory is full, wasting GC time.

This PR corrects the problem by unpersisting both the edges and the replicated vertices of previous iterations. This is safe because the edges and replicated vertices of the current iteration are cached by the call to `g.cache()` and then materialized by the call to `messages.count()`. Therefore no unmaterialized RDDs depend on `prevG.edges`. I verified that no recomputation occurs by running PageRank with a custom patch to Spark that warns when a partition is recomputed.

Thanks to Tim Weninger for reporting this bug.

Author: Ankur Dave <ankurdave@gmail.com>

Closes #972 from ankurdave/SPARK-2025 and squashes the following commits:

13d5b07 [Ankur Dave] Unpersist edges of previous graph in Pregel
SPARK-2043: ExternalAppendOnlyMap doesn't always find matching keys

The current implementation reads one key with the next hash code as it finishes reading the keys with the current hash code, which may cause it to miss some matches of the next key. This can cause operations like join to give the wrong result when reduce tasks spill to disk and there are hash collisions, as values won't be matched together. This PR fixes it by not reading in that next key, using a peeking iterator instead.

Author: Matei Zaharia <matei@databricks.com>

Closes #986 from mateiz/spark-2043 and squashes the following commits:

0959514 [Matei Zaharia] Added unit test for having many hash collisions
892debb [Matei Zaharia] SPARK-2043: don't read a key with the next hash code in ExternalAppendOnlyMap, instead use a buffered iterator to only read values with the current hash code.
merge master