engine: Fix confusing names in async tasks

Fix confusing name for action and command
parameters in AsyncTasks and Command Entities

Change-Id: I6e619857ae36f1b69a4370ddcf53aee45c2c2c6f
Bug-Url: https://bugzilla.redhat.com/1127774
Signed-off-by: Ravi Nori <rnori@redhat.com>