LU-1905 build: Always create libcfs.a

LU-1905 build: Always create libcfs.a

Lustre and LNET utilites have become dependent on libcfs.a but
one can easily disable libcfs.a from being built by disabling
liblustre creation. This patch have Lustre always build libcfs.a.

Signed-off-by: James Simmons <uja.ornl@gmail.com>
Change-Id: Id80f9baa16da238eca708409e0b5d5248e437c5a
Reviewed-on: http://review.whamcloud.com/3953
Tested-by: Hudson
Reviewed-by: Doug Oucharek <doug.s.oucharek@intel.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Brian J. Murrell <brian@whamcloud.com>
Reviewed-by: Artem Blagodarenko <artem_blagodarenko@xyratex.com>
Tested-by: Maloo <whamcloud.maloo@gmail.com>