engine : Command Executor should persist command before submitting to threadpool

Command Coordinator should persist command before
submitting command to thread pool for execution. On
server restarted the commands that have not started
execution are failed

Change-Id: I4d510836dc822a95198dc1db4a4f74206466f0c9
Bug-Url: https://bugzilla.redhat.com/1113256
Signed-off-by: Ravi Nori <rnori@redhat.com>