glusterd/snapshot: Perform missed snap deletes and restores.

Replacing is_volume_restored(gf_boolean_t) with
restored_from_snap(uuid_t) in glusterd_volinfo_

Also removed gd_restore_snap_volume from glusterd-volgen.c
to glusterd-snapshot.c

Change-Id: Ic615a1658cfaffa98d4590506ac82f20bf709ad6
BUG: 1089906
Signed-off-by: Avra Sengupta <asengupt@redhat.com>
Reviewed-on: http://review.gluster.org/7455
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Krishnan Parthasarathi <kparthas@redhat.com>
Reviewed-by: Rajesh Joseph <rjoseph@redhat.com>
Reviewed-by: Vijay Bellur <vbellur@redhat.com>