Blocker Description
Very similar to HBASE-1928, but for the general case (not just ROOT/META):
If a region is in transition on a RS when the RS crashes, the master does not remove it from regionsInTransition when processing the RS shutdown. This is fairly easy to trigger by bringing up a RS and kill -9ing it just as it starts to get regions assigned. Those regions will get permanently lost since they're stuck in regionsInTransition and thus don't get assigned by the metascanner.