LU-2800 autoconf: remove LC_SECURITY_PLUG test

LU-2800 autoconf: remove LC_SECURITY_PLUG test

Only the SLES 10 kernel took a vfsmount for various vfs operations
to support AppArmor before the path variants were available.
We can remove the test and the dead code.

Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: James Simmons <uja.ornl@gmail.com>
Change-Id: I5d4b1c1c9c4994582c51c39ef3b7375b2e0997d3
Reviewed-on: http://review.whamcloud.com/5360
Tested-by: Maloo <whamcloud.maloo@gmail.com>
Tested-by: Hudson
Reviewed-by: Bob Glossman <bob.glossman@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>