glusterd/uss: if snapd is not running, return success from glusterd_handle_snapd_option

glusterd_handle_snapd_option was returning failure if snapd is not running
because of which gluster commands were failing.

Change-Id: I22286f4ecf28b57dfb6fb8ceb52ca8bdc66aec5d
BUG: 1168803
Signed-off-by: Atin Mukherjee <amukherj@redhat.com>
Reviewed-on: http://review.gluster.org/9206
Reviewed-by: Kaushal M <kaushal@redhat.com>
Reviewed-by: Avra Sengupta <asengupt@redhat.com>
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Vijaikumar Mallikarjuna <vmallika@redhat.com>
Reviewed-by: Krishnan Parthasarathi <kparthas@redhat.com>
Tested-by: Krishnan Parthasarathi <kparthas@redhat.com>