[SPARK-2412] CoalescedRDD throws exception with certain pref locs

If the first pass of CoalescedRDD does not find the target number of locations AND the second pass finds new locations, an exception is thrown, as "groupHash.get(nxt_replica).get" is not valid.

The fix is just to add an ArrayBuffer to groupHash for that replica if it didn't already exist.

Author: Aaron Davidson <aaron@databricks.com>

Closes #1337 from aarondav/2412 and squashes the following commits:

f587b5d [Aaron Davidson] getOrElseUpdate
3ad8a3c [Aaron Davidson] [SPARK-2412] CoalescedRDD throws exception with certain pref locs
SPARK-2526: Simplify options in make-distribution.sh

Right now we have a bunch of parallel logic in make-distribution.sh
that's just extra work to maintain. We should just pass through
Maven profiles in this case and keep the script simple. See
the JIRA for more details.

Author: Patrick Wendell <pwendell@gmail.com>

Closes #1445 from pwendell/make-distribution.sh and squashes the following commits:

f1294ea [Patrick Wendell] Simplify options in make-distribution.sh.
[SPARK-2423] Clean up SparkSubmit for readability

It is currently non-trivial to trace through how different combinations of cluster managers (e.g. yarn) and deploy modes (e.g. cluster) are processed in SparkSubmit. Moving forward, it will be easier to extend SparkSubmit if we first re-organize the code by grouping related logic together.

This is a precursor to fixing standalone-cluster mode, which is currently broken (SPARK-2260).

Author: Andrew Or <andrewor14@gmail.com>

Closes #1349 from andrewor14/submit-cleanup and squashes the following commits:

8f99200 [Andrew Or] script -> program (minor)
30f2e65 [Andrew Or] Merge branch 'master' of github.com:apache/spark into submit-cleanup
fe484a1 [Andrew Or] Move deploy mode checks after yarn code
7167824 [Andrew Or] Re-order config options and update comments
0b01ff8 [Andrew Or] Clean up SparkSubmit for readability