LU-6490 build: enable gss build on sles12

LU-6490 build: enable gss build on sles12

Now that the build failures of gss on sles12 are fixed
change lbuild to stop disabling the gss build there.

Signed-off-by: Bob Glossman <bob.glossman@intel.com>
Change-Id: Icf25c038c28b8e230550de0bbe5b0b2fbe0c0b78
Reviewed-on: http://review.whamcloud.com/15354
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: James Simmons <uja.ornl@yahoo.com>
Reviewed-by: Sebastien Buisson <sebastien.buisson@bull.net>
Reviewed-by: Minh Diep <minh.diep@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>