engine:  Failures when trying to run stateless VM

The following bug was caused because of change in infrastracture
of AsyncTaskManager, from now parameters are not kept and not duplicate
on commands parameters.
Such change cause problem in run stateless VM, in order to fix it
RunVmCommand was updated accordingly

Change-Id: I5a6b9c715bfcc692c98ac91cd33c84a5ebfaf22d
Bug-Url: https://bugzilla.redhat.com/919842
Signed-off-by: Michael Kublin <mkublin@redhat.com>