[glusterd/snapshot]: snapshot create CLI msg correction

Uniformity in cli output while creating snapshots

Change-Id: Ic0fd09bbde9a1f55c441e1745f93c588d2e4c1a1
BUG: 1090041
Signed-off-by: Joseph Fernandes <josferna@redhat.com>
Reviewed-on: http://review.gluster.org/7518
Reviewed-by: Rajesh Joseph <rjoseph@redhat.com>
Reviewed-by: Vijay Bellur <vbellur@redhat.com>
Tested-by: Gluster Build System <jenkins@build.gluster.com>