LU-4423 libcfs: use ahash for libcfs crypto layer

LU-4423 libcfs: use ahash for libcfs crypto layer

This patch replaces uses of the long obsolete hash interface with
ahash.

Linux-commit : 6dae10001e84253992142c7343fdae16a13f3d73
Linux-commit : 9dffdb38d864ae89e16ff7b3a09451270736e35b

Change-Id: I9fba47cc05f755ebfd2350c7881708745283d666
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: James Simmons <uja.ornl@yahoo.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-on: http://review.whamcloud.com/19716
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Alexander Boyko <alexander.boyko@seagate.com>
Reviewed-by: Frank Zago <fzago@cray.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>