LU-1346 libcfs: cleanup libcfs primitive (linux-prim.h)

LU-1346 libcfs: cleanup libcfs primitive (linux-prim.h)

Affected primitives:

cfs_mb, cfs_in_interrupt, cfs_might_sleep, cfs_group_info_t,
cfs_get_group_info, cfs_put_group_info, cfs_set_current_groups,
cfs_groups_free, cfs_groups_alloc, cfs_get_random_bytes_prim

Signed-off-by: Liu Xuezhao <xuezhao.liu@emc.com>
Signed-off-by: Peng Tao <tao.peng@emc.com>
Signed-off-by: James Simmons <uja.ornl@gmail.com>
Change-Id: I52293cad577f2027cabf1b124dbb1b7354fef3a5
Reviewed-on: http://review.whamcloud.com/6957
Tested-by: Hudson
Tested-by: Maloo <whamcloud.maloo@gmail.com>
Reviewed-by: Keith Mannthey <keith.mannthey@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>