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