VM stuck in 'Waiting for Launch' state in RHEV Admin Portal, yet were actually 'Up' on the host.

Issue

• VMs that had just been shutdown were restarted on the same host and became stuck in a Waiting for Launch state in the RHEV Admin Portal.

• However, these VMs were in an Up state on the host and were functioning as expected, e.g. they could be accessed via ssh.

• Other VMs that were subsequently started on this host also became stuck in the same state, but were able to be started on a different host without a problem.

• What was noticed when both VMs were shutdown before they were restarted was that they both reported the following error, presumably relative to an attempt to open a Spice console;

jsonrpc.Executor-worker-2::DEBUG::2016-01-25 14:43:53,841::__init__::481::jsonrpc.JsonRpcServer::(_serveRequest) Calling 'VM.setTicket' in bridge with {u'vmID': u'00f9001f-9b86-4fe1-a9aa-3240fcf7a7ef', u'password': '********', u'params':
 {u'userName': u'admin', u'userId': u'fdfc627c-d875-11e0-90f0-83df133b58cc'}, u'existingConnAction': u'disconnect', u'ttl': u'120'}
jsonrpc.Executor-worker-2::ERROR::2016-01-25 14:43:53,842::__init__::506::jsonrpc.JsonRpcServer::(_serveRequest) Internal server error
Traceback (most recent call last):
  File "/usr/lib/python2.7/site-packages/yajsonrpc/__init__.py", line 501, in _serveRequest
  File "/usr/share/vdsm/rpc/Bridge.py", line 271, in _dynamicMethod
  File "/usr/share/vdsm/API.py", line 642, in setTicket
  File "/usr/share/vdsm/virt/vm.py", line 4954, in setTicket
AttributeError: 'NoneType' object has no attribute 'XMLDesc'