LU-1199 build: Remove unused LB_LDISKFS_RELEASE macros

The products of the LB_LDISKFS_RELEASE macros are unused.  They
also make some bad assumtions that complicate building against
a future lustre-devel package.  So we remove them.

If Lustre needs to know ldiskfs's version in the future, we
should add explicit version defines to the new ldiskfs_config.h.in
header that is in the works (or possibly landed by now).

Change-Id: I40b96dc72f5076ba9a9dda3f41b31088fdfd4341
Signed-off-by: Christopher J. Morrone <morrone2@llnl.gov>
Reviewed-on: http://review.whamcloud.com/5881
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Tested-by: Hudson
Tested-by: Maloo <whamcloud.maloo@gmail.com>
Reviewed-by: James Simmons <uja.ornl@gmail.com>