cli: x-identifier auto-completion doesn't work in permissions(#1027281)

append of -identifier suffix for vm object at
permission auto-completion doesn't work for
list/show/remove commands.

Change-Id: Id9b1578dada8a3810bec766951e346c59abad61f
Bug-Url: https://bugzilla.redhat.com/1027281
Signed-off-by: Ravi Nori <rnori@redhat.com>