core: no repeated steps for task handlers

Change-Id: I0b68bcefcb23fcbe7a4b01e32d21a846b7d16d7c
Signed-off-by: Federico Simoncelli <fsimonce@redhat.com>
backend: pass context from ImportRepoImage

Change-Id: Id91fd1dab1102a64b348f8a203b4413f624e75ad
Signed-off-by: Federico Simoncelli <fsimonce@redhat.com>