Remove middleware directory missed in prev commit

Change-Id: Ic0e9e78acc06e180f7acfec3e2a5901b7f80598b
Signed-off-by: Peter Portante <peter.portante@redhat.com>
Reviewed-on: http://review.gluster.org/5079
Reviewed-by: Luis Pabon <lpabon@redhat.com>
Tested-by: Luis Pabon <lpabon@redhat.com>