[SPARK-2251] fix concurrency issues in random sampler (branch-1.0)

The following code is very likely to throw an exception:

~~~
val rdd = sc.parallelize(0 until 111, 10).sample(false, 0.1)
rdd.zip(rdd).count()
~~~

because the same random number generator is used in compute partitions. This fix doesn't change the type signature.

@pwendell

Author: Xiangrui Meng <meng@databricks.com>

Closes #1234 from mengxr/fix-sample-1.0 and squashes the following commits:

88795e2 [Xiangrui Meng] fix concurrency issues in random sampler
[SPARK-2295] [SQL] Make JavaBeans nullability stricter.

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

Closes #1235 from ueshin/issues/SPARK-2295 and squashes the following commits:

201c508 [Takuya UESHIN] Make JavaBeans nullability stricter.

(cherry picked from commit 32a1ad75313472b1b098f7ec99335686d3fe4fc3)
Signed-off-by: Michael Armbrust <michael@databricks.com>
[SPARK-2286][UI] Report exception/errors for failed tasks that are not ExceptionFailure

Also added inline doc for each TaskEndReason.

Author: Reynold Xin <rxin@apache.org>

Closes #1225 from rxin/SPARK-2286 and squashes the following commits:

6a7959d [Reynold Xin] Fix unit test failure.
cf9d5eb [Reynold Xin] Merge branch 'master' into SPARK-2286
a61fae1 [Reynold Xin] Move to line above ...
38c7391 [Reynold Xin] [SPARK-2286][UI] Report exception/errors for failed tasks that are not ExceptionFailure.
(cherry picked from commit 6587ef7c1783961e6ef250afa387271a1bd6e277)

Conflicts:

	core/src/main/scala/org/apache/spark/ui/jobs/StageTable.scala
Updating versions for 1.0.1 release
Small error in previous commit
Fixing AWS instance type information based upon current EC2 data

Fixed a problem in previous file in which some information regarding AWS instance types were wrong. Such information was updated base upon current AWS EC2 data.

Author: Zichuan Ye <jerry@tangentds.com>

Closes #1156 from jerry86/master and squashes the following commits:

ff36e95 [Zichuan Ye] Fixing AWS instance type information based upon current EC2 data
(cherry picked from commit 62d4a0fa9947e64c1533f66ae577557bcfb271c9)

Conflicts:

	ec2/spark_ec2.py
CHANGES.txt for release 1.0.1