indexed contrib tests fail intermittently

[Andrew Purtell <ap...@apache.org>]

On 0.20 head, the indexed contrib tests fail intermittently -- a test deadlocks and/or fails to terminate, leading to a direct test failure or the failure of the next to initialize. I thought this might be HBASE-2322. Likelihood of failure depends on which server I run the test, definitely a race. 

Somewhere in the change set between 0.20_pre_durability and 0.20 branch head is a difference that allows the tests to pass. (If it were a consistent failure I could easily git bisect to find the commit.) If I stitch 0.20 branch together leaving out group commit and other write path changes also I can seemingly avoid the problem. 

The patch on HBASE-2248 trips up against indexed contrib in a different way.

But I wonder if it is the test or even the contrib.

   - Andy