LU-6245 libcfs: cleanup up libcfs hash code for upstream

LU-6245 libcfs: cleanup up libcfs hash code for upstream

This patch brings the libcfs hash handling up to linux
kernel coding style. Various typedefs and macros have
been removed. Also support for the change of in 3.18
kernels of hlist_add_behind are also handled.

Change-Id: If50e34cfe4aaa593f755c9214f350ce21da56f20
Signed-off-by: James Simmons <uja.ornl@yahoo.com>
Reviewed-on: http://review.whamcloud.com/14624
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Bob Glossman <bob.glossman@intel.com>
Reviewed-by: frank zago <fzago@cray.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>