Cannot start RHEV VMs after a maintenance period today

Issue

RHEV VMs would not start after performance setup maintenance, with error:

Failed to run VM myVm (User: user1).

In vdsm.log the following error is inspected:

Thread-2921::ERROR::2014-06-06 17:19:17,044::task::850::TaskManager.Task::(_setError) Task=`00d3b6b3-4a97-4eae-95e5-5f0a207788fc`::Unexpected error
Traceback (most recent call last):
  File "/usr/share/vdsm/storage/task.py", line 857, in _run
    return fn(*args, **kargs)
  File "/usr/share/vdsm/logUtils.py", line 45, in wrapper
    res = f(*args, **kwargs)
  File "/usr/share/vdsm/storage/hsm.py", line 2564, in getStoragePoolInfo
    poolInfo = pool.getInfo()
  File "/usr/share/vdsm/storage/sp.py", line 1450, in getInfo
    'name': pmd[PMDK_POOL_DESCRIPTION],
  File "/usr/share/vdsm/storage/persistentDict.py", line 89, in __getitem__
    return dec(self._dict[key])
  File "/usr/share/vdsm/storage/persistentDict.py", line 201, in __getitem__
    raise KeyError(key)
KeyError: 'POOL_DESCRIPTION'