gsyncd / geo-rep: fix cli query for volinfo fetch

With an unprivileged geo-replication session, monitor
was using user@slave for --remote-host option for gluster
cli, thereby failing to sucessfully connect to the slave
glusterd.

This patch fixes the issue by selecting the hostname/IP
from the speicified slave endpoint url.

- For privileged geo-replication sessions, this patch
has no effect as the slave endpoint url is just the
hostname/IP.

Change-Id: I88f66c406a8d9a34db7fc626965f949075e3ceac
BUG: 1077452
Signed-off-by: Venky Shankar <vshankar@redhat.com>
Reviewed-on: http://review.gluster.org/7818
Reviewed-by: Aravinda VK <avishwan@redhat.com>
Reviewed-by: Kotresh HR <khiremat@redhat.com>
Tested-by: Gluster Build System <jenkins@build.gluster.com>