core: DeactivateStorageDomainWithOvfUpdate - locks

The lock taken by the command should be released at the end of the
endAction() method, therfore we should avoid passing it to the child
command (so it won't be released by it). Also, avoid releasing the in
memory lock while there are still tasks.

Change-Id: Id8199e372d72f673aeb7b16d12cc8f5ffa043117
Bug-Url: https://bugzilla.redhat.com/show_bug.cgi?id=1138124
Signed-off-by: Liron Aravot <laravot@redhat.com>