Support for LDAP tests

* Allow Beeswax connections to optionally use LDAP
* Run custom cluster tests from the aux repo, if it exists

Change-Id: I054af64e030ad0cd722ae8dd75afda9c58ea2913
Reviewed-on: http://gerrit.ent.cloudera.com:8080/2547
Reviewed-by: Ishaan Joshi <ishaan@cloudera.com>
Tested-by: jenkins
CDH-18785: Move optimize module from PlanExecFragment Prepare() to Open().

We start up plan fragments in level order, calling Prepare() one level at a time.
Currently, OptimizeLlvmModule is called at the end of Prepare(). OptimizeLlvmModule()
compiles the IR which can be expensive (~1 second). By doing this level order, we
serialize the compile time and for big plans, this can add up.

This change is trivial by moving the OptimizeLlvmModule() call to the Open() phase.

The snipped from the issue is (running on an empty table):
The codegen time is rows available & first row fetched.

Before:
Query Timeline:
 Query Timeline: 4s182ms
  - Start execution: 2.648ms (2.648ms)
  - Planning finished: 321.5ms (318.357ms)
  - Rows available: 4s161ms (3s840ms)
  - First row fetched: 4s163ms (1.368ms)
  - Unregister query: 4s167ms (3.786ms)

With this patch:
Query Timeline: 2s111ms
  - Start execution: 2.623ms (2.623ms)
  - Planning finished: 369.284ms (366.660ms)
  - Rows available: 2s018ms (1s649ms)
  - First row fetched: 2s093ms (74.962ms)
  - Unregister query: 2s097ms (3.805ms)

Change-Id: Ia78782e4708313ed197877749e80a9a68eeec551
Reviewed-on: http://gerrit.ent.cloudera.com:8080/2584
Reviewed-by: Nong Li <nong@cloudera.com>
Tested-by: jenkins
CDH-18969: Incorrect query result in Impala

This commit fixes issue CDH-18969 where Impala returns wrong results
when querying an HBase table. This issue is triggered when a column family
sorts lexicographically before ":key", which is the column family of the
row key, thereby causing the wrong column to be used as a row key by the
backend.

The following changes are included:
1. Modified the load function in HBaseTable.java to make sure the
catalog object of an HBase table always stores the row key column first.

Change-Id: Icd7ebc973d81672c04d5c7c8bbabd813338d5eac
Reviewed-on: http://gerrit.ent.cloudera.com:8080/2513
Reviewed-by: Dimitris Tsirogiannis <dtsirogiannis@cloudera.com>
Tested-by: jenkins