Issue

• The vdsm logs contained the following extract while a host was in a non-responsive state;

JsonRpcServer::ERROR::2016-05-26 19:55:16,322::__init__::600::jsonrpc.JsonRpcServer::(_runRequest) could not allocate request thread
Traceback (most recent call last):
  File "/usr/lib/python2.7/site-packages/yajsonrpc/__init__.py", line 598, in _runRequest
    self._threadFactory(partial(self._serveRequest, ctx, request))
  File "/usr/lib/python2.7/site-packages/vdsm/executor.py", line 101, in dispatch
    self._tasks.put((callable, timeout))
  File "/usr/lib/python2.7/site-packages/vdsm/executor.py", line 239, in put
    raise TooManyTasks()
TooManyTasks