glusterd: persistent client xlator/ afr changelog names

-Add a unique brick-id field to glusterd_brickinfo_t
-Persist the id to the brickinfo file
-Use the brick-id as the client xlator name during vol create, add-brick and
 replace-brick operations.
-For older volumes,generate the id in-memory during glusterd restore but defer
 writing it to the brickinfo file until the next volume set operation.
-send and receive the brick-ids during peer probe.

Feature page:
www.gluster.org/community/documentation/index.php/Features/persistent-AFR-changelog-xattributes

Related patch:
http://review.gluster.org/#/c/7122

Change-Id: Ib7f1570004e33f4144476410eec2b84df4e41448
BUG: 1066778
Signed-off-by: Ravishankar N <ravishankar@redhat.com>
Reviewed-on: http://review.gluster.org/7155
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Pranith Kumar Karampuri <pkarampu@redhat.com>
Reviewed-by: Kaushal M <kaushal@redhat.com>
Reviewed-by: Vijay Bellur <vbellur@redhat.com>