CDH-19856: Disable Hive's stats autogathering.

Change-Id: I04e91f91d29b7863848a750e362c9d94469df7f2
Reviewed-on: http://gerrit.ent.cloudera.com:8080/3156
Reviewed-by: Alex Behm <alex.behm@cloudera.com>
Tested-by: jenkins
Change UnionNode to open its first child in UnionNode::Open().

This patch ensures that rows are available for clients to fetch
after we advance the query to FINISHED if the coordinator
fragment is rooted at a UnionNode.

Change-Id: I9b4ad3f70b46c7e7720bdd5ca9ad85479c2cb7fd
Reviewed-on: http://gerrit.ent.cloudera.com:8080/3139
Reviewed-by: Alex Behm <alex.behm@cloudera.com>
Tested-by: jenkins
IMPALA-1052: Display a warning when an order-by without limit is ignored

Displays a warning and the ignored order by clause

Change-Id: I3738d60e914de02bec552478279d8c4314426676
Reviewed-on: http://gerrit.ent.cloudera.com:8080/3102
Reviewed-by: Srinath Shankar <sshankar@cloudera.com>
Tested-by: jenkins
Force load data if the current HEAD has a schema change.

This patch checks the test-warehouse's stored githash (if it exists) to determine if the
current patch has changed the schema if a table. If a change is detected, we force load
all the data.

Change-Id: I314f9f3364d3e6b2d66de38a9e6d9f57c4e279a7
Reviewed-on: http://gerrit.ent.cloudera.com:8080/3049
Reviewed-by: Ishaan Joshi <ishaan@cloudera.com>
Tested-by: jenkins
Reviewed-on: http://gerrit.ent.cloudera.com:8080/3163
Run local tests at lower concurrency.

Currently, we launch #nproc processes to run tests locally. This patch changes the default
to #proc/2, to not overload the system.

Change-Id: I8bca23eb7462a0c497df93f82a60d85835bedbe9
Reviewed-on: http://gerrit.ent.cloudera.com:8080/2972
Reviewed-by: Ishaan Joshi <ishaan@cloudera.com>
Tested-by: Ishaan Joshi <ishaan@cloudera.com>
Reviewed-on: http://gerrit.ent.cloudera.com:8080/3164
Tested-by: jenkins