geo-rep/glusterd: Pause and Resume feature for geo-replication

        This patch introduces pause and resume cli command
        for geo-replication.

Signed-off-by: Kotresh H R <khiremat@redhat.com>

Change-Id: I4f5e58e9175fe85077d56088473252391fb57de7
BUG: 1093602
Signed-off-by: Kotresh H R <khiremat@redhat.com>
Reviewed-on: http://review.gluster.org/7643
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Atin Mukherjee <amukherj@redhat.com>
Reviewed-by: Avra Sengupta <asengupt@redhat.com>
Reviewed-by: Venky Shankar <vshankar@redhat.com>
Tested-by: Venky Shankar <vshankar@redhat.com>