engine: Host activate -check gluster availability

If cluster supports gluster service, need to
check if gluster is running, while activating host.
If gluster command fails on server, the host state
should not be changed to UP on activate.

Change-Id: If673e32ed6480187ddcf6f9ecf8f0007e203b98d
Bug-Url: https://bugzilla.redhat.com/975382
Signed-off-by: Sahina Bose <sabose@redhat.com>