Cluster/DHT : Additional log messages

Adding log messages in the rename and lookup calls to
help with debugging.

Change-Id: I13b1c6f98fb49ead45362550c46359ab1f9028c0
BUG: 1130888
Signed-off-by: Nithya Balachandran <nbalacha@redhat.com>
Reviewed-on: http://review.gluster.org/8516
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Raghavendra G <rgowdapp@redhat.com>