extras: Changed the exit status in start function to 0.

Problem:
We were returning "1" when "glusterd start" was being called with service
already running. As per
http://refspecs.linuxbase.org/LSB_4.1.0/LSB-Core-generic/LSB-Core-generic/iniscrptact.html
we should consider it to be a success case and return 0.

Fix:
Just changed the return status from 1 to 0.

Change-Id: I8d6d2014f0c32ba53834503e721e2a71df7330a8
BUG: 845653
Signed-off-by: Raghavendra Talur <rtalur@redhat.com>
Reviewed-on: http://review.gluster.org/4348
Reviewed-by: Niels de Vos <ndevos@redhat.com>
Tested-by: Gluster Build System <jenkins@build.gluster.com>