glusterd/gverify.sh: Stops session being created with invalid slave details

create force will fail with proper message, if the ip is not
reachable, or is unable to fetch slave details.

Change-Id: I44a3ba777b37702ffd0e48e9cb46c51e293327d4
BUG: 988314
Signed-off-by: Avra Sengupta <asengupt@redhat.com>
Signed-off-by: Venky Shankar <vshankar@redhat.com>
Reviewed-on: http://review.gluster.org/5516
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Anand Avati <avati@redhat.com>