LU-2800 autoconf: remove LC_PROCFS_USERS test

LU-2800 autoconf: remove LC_PROCFS_USERS test

In-procfs locking has been upstream since v2.6.23

We can remove the test and the dead code (lots of it). Further
review should be made to determine whether _lprocfs_lock is
still necessary at all.

Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: James Simmons <uja.ornl@gmail.com>
Change-Id: I6384a9776fcb45de74d10beee8c1b8477b1ffad6
Reviewed-on: http://review.whamcloud.com/5353
Reviewed-by: Bob Glossman <bob.glossman@intel.com>
Tested-by: Hudson
Tested-by: Maloo <whamcloud.maloo@gmail.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>