glusterd/snapshot : Copy geo-rep status and config files before taking a snapshot.

geo-rep status and conf files needs to be copied before taking a snapshot.
The idea here is, when the snapshot is restored, these config and status
files needs to be placed back in geo-replication folder so that
geo-replication can start with the same state it was when taking
a snapshot.

Details :
Before a snapshot is taken, Copy the status and config files present
in /var/lib/glusterd/geo-replication/.

The files copied are gsyncd.conf and status files of each session
belonging to a volume whose snapshot is about to be taken.

Change-Id: I0234ecd846883350c59777c2505290729de0ce05
BUG: 1061685
Signed-off-by: Sachin Pandit <spandit@redhat.com>
Reviewed-on: http://review.gluster.org/7495
Reviewed-by: Kotresh HR <khiremat@redhat.com>
Reviewed-by: Vijaikumar Mallikarjuna <vmallika@redhat.com>
Reviewed-by: Rajesh Joseph <rjoseph@redhat.com>
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Vijay Bellur <vbellur@redhat.com>