cluster/dht: synchronize rename and file-migration

Change-Id: I4f243c946f76d440680b651235f925e3d0ebf0fd
BUG: 1140348
Signed-off-by: Raghavendra G <rgowdapp@redhat.com>
Reviewed-on: http://review.gluster.org/8523
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Vijay Bellur <vbellur@redhat.com>
(cherry picked from commit 21c8946b0bc05d0bc8f84906e16b8c2cbca4c9f9)
Signed-off-by: Nithya Balachandran <nbalacha@redhat.com>
Reviewed-on: http://review.gluster.org/8726
Reviewed-by: Krutika Dhananjay <kdhananj@redhat.com>
Reviewed-by: Niels de Vos <ndevos@redhat.com>