LU-8130 nrs: convert NRS CRR to rhashtable

LU-8130 nrs: convert NRS CRR to rhashtable

Move away for the cfs hash implementation to rhashtable
for NRS CRR handling. Since rhashtable is lockless it
should also increase performance.

Test-Parameters:trivial testlist=sanityn envdefinitions=ONLY=77b

Change-Id: I817d35c8e36d7cb3397ffe8d00eee225245559b8
Signed-off-by: James Simmons <uja.ornl@yahoo.com>
Reviewed-on: https://review.whamcloud.com/33485
Tested-by: Jenkins
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Nikitas Angelinas <nangelinas@cray.com>