mgmt/glusterd: Expose post-op-delay through cli

Change-Id: I13e3699bd58d53896ae54e1bfafb3cd1c9580c7c
BUG: 905307
Signed-off-by: Pranith Kumar K <pkarampu@redhat.com>
Reviewed-on: http://review.gluster.org/4443
Reviewed-by: Krishnan Parthasarathi <kparthas@redhat.com>
Tested-by: Gluster Build System <jenkins@build.gluster.com>