engine: Handling generic gluster errors from vdsm

Added missing definitions of generic gluster error codes
returned from vdsm.

Change-Id: I8bb92c52d44171de8e880be8f003d4ac52e0e08f
Bug-Url: https://bugzilla.redhat.com/914667
Signed-off-by: Sahina Bose <sahina@gmail.com>