Event_notify can be used by others to communicate with glusterd. A cbk event is also added for future use. req has a op, and dict. rsp has op_ret, op_errno, and dict. With this, rebalance process can update the status before exiting. Signed-off-by: shishir gowda <shishirng@gluster.com> Change-Id: If5c0ec00514eb3a109a790b2ea273317611e4562 BUG: 807126 Reviewed-on: http://review.gluster.com/3013 Tested-by: Gluster Build System <jenkins@build.gluster.com> Reviewed-by: Amar Tumballi <amarts@redhat.com> Reviewed-by: Vijay Bellur <vijay@gluster.com>