HBASE-12198 Fix the bug of not updating location cache

Summary:  # Clear the cache of the server when failed

Test Plan: Add testcase `TestHTableMultiplexerFlushCache` to reproduce the bug.

Differential Revision: https://reviews.facebook.net/D24603

Signed-off-by: Elliott Clark <elliott@fb.com>
Signed-off-by: Elliott Clark <eclark@apache.org>
HBASE-12109 user_permission command for namespace does not return correct result (Vandana Ayyalasomayajula)
HBASE-11990 Make setting the start and stop row for a specific prefix easier (Niels Basjes)
HBASE-12218 Make HBaseCommonTestingUtil#deleteDir try harder