Class UnassignRegionHandler

All Implemented Interfaces:
Comparable<EventHandler>, Runnable

@Private public class UnassignRegionHandler extends EventHandler
Handles closing of a region on a region server.

Just done the same thing with the old CloseRegionHandler, with some modifications on fencing and retrying. But we need to keep the CloseRegionHandler as is to keep compatible with the zk less assignment for 1.x, otherwise it is not possible to do rolling upgrade.