LU-11635 gss: proper gss build for client-only

Fix gss build system for both rpms and debs in case of client-only
build.
Fix consists in passing along '--{enable,disable}-gss' option, and
including lgssc.conf file in case of client-only build.

Test-Parameters: trivial
Signed-off-by: Sebastien Buisson <sbuisson@ddn.com>
Change-Id: Id884d282e312177c262b1f4725b8f19e2c14fd37
Reviewed-on: https://review.whamcloud.com/33608
Tested-by: Jenkins
Reviewed-by: James Simmons <uja.ornl@yahoo.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Li Dongyang <dongyangli@ddn.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>