Gracefully handle the ring file not found error.

Change-Id: I35c33f3938709d5d9a9a55640a503f186df9a965
Signed-off-by: Mohammed Junaid <junaid@redhat.com>
Reviewed-on: http://review.gluster.org/5368
Reviewed-by: Luis Pabon <lpabon@redhat.com>
Tested-by: Luis Pabon <lpabon@redhat.com>