LU-4470 build: wrong linux symbol file search

LU-4470 build: wrong linux symbol file search

Long standing build flaw just discovered.  The autoconf function
LB_CHECK_SYMBOL_EXPORT looks for the linux symbol table in the wrong place.
In most builds this doesn't matter as the wrong path being used exactly
matches the correct path.  In SLES builds it does matter a lot.
Failing to find the linux symbol table can lead to incorrect autoconf results.

Signed-off-by: Bob Glossman <bob.glossman@intel.com>
Change-Id: Iab43a2c118c9b8be54a9596b4682b68a11946a94
Reviewed-on: http://review.whamcloud.com/9056
Tested-by: Jenkins
Reviewed-by: Dmitry Eremin <dmitry.eremin@intel.com>
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Minh Diep <minh.diep@intel.com>
Reviewed-by: Brian J. Murrell <brian.murrell@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>