LU-5577 libcfs: fix warnings in libcfs/curproc.h

Fix compiler warnings that annoying from searching other issues.

Signed-off-by: Dmitry Eremin <dmitry.eremin@intel.com>
Change-Id: I17cdc1d94b58d2c2f3284665090ad7eef991d5ac
Reviewed-on: http://review.whamcloud.com/12379
Reviewed-by: Bob Glossman <bob.glossman@intel.com>
Tested-by: Jenkins
Reviewed-by: James Simmons <uja.ornl@gmail.com>
Reviewed-by: John L. Hammond <john.hammond@intel.com>
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>