GFS2: LSF and LBD are now one and the same

As a result of this recent patch:
http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commitdiff;h=b3a6ffe1


We only need to depend on LBD.

Reported-by: Fabio M. Di Nitto <fdinitto@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>