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.

Change-Id: I9068f2b9aace740b67d88598844c0b8fc1d95b49
Signed-off-by: Bob Glossman <bob.glossman@intel.com>
Reviewed-on: http://review.whamcloud.com/9288
Tested-by: Jenkins
Reviewed-by: Dmitry Eremin <dmitry.eremin@intel.com>
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>