engine: AsyncTask manger part 2 - vms scenario

The following fix should solve a following paroblem:
1. Part of vm scenarios are creating async task with out parent and child task
   thats why appropriate check should be added to EntityAsyncTask
2. Fixing also VdcActionParametersBase accordingly, because of imageParameters are not
   passed to DB

Change-Id: I43320dfb32a2477308cd881cb7d27c49f3f9f346
Signed-off-by: Michael Kublin <mkublin@redhat.com>