LU-56 libcfs: more common APIs in libcfs

LU-56 libcfs: more common APIs in libcfs

Implementation of some common APIs:
- per-cpu-partition (percpt) data allocators
- implementation of per-cpu-partition lock
- a few other functions

Signed-off-by: Liang Zhen <liang@whamcloud.com>
Change-Id: Ib303b79ee9be87cc306da7e2feb20c8c296b8ac6
Reviewed-on: http://review.whamcloud.com/2558
Tested-by: Hudson
Reviewed-by: Doug Oucharek <doug@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Tested-by: Maloo <whamcloud.maloo@gmail.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>