USS : Kill snapd during glusterd restart if USS is disabled

Problem : When glusterd is down on one of the nodes and during that
time if USS is disabled then snapd will still be running
in the node where glusterd was down.

Solution : during restart of glusterd check if USS is disabled,
if so then issue a kill for snapd.

NOTE : The test case which I wrote in my previous patchset
is facing some spurious failures, hence I thought of removing
that test case. I'll add the test case once the issue is resolved.

Change-Id: I2870ebb4b257d863cdfc319e8485b19e932576e9
BUG: 1161015
Signed-off-by: Sachin Pandit <spandit@redhat.com>
Reviewed-on: http://review.gluster.org/9062
Reviewed-by: Rajesh Joseph <rjoseph@redhat.com>
Reviewed-by: Avra Sengupta <asengupt@redhat.com>
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Krishnan Parthasarathi <kparthas@redhat.com>
Tested-by: Krishnan Parthasarathi <kparthas@redhat.com>