GFS2: Eliminate gfs2_rg_lops

With recent changes to the transactions, it appears that we
are no longer using the "log ops" for resource groups. Since the
log commit code processes the array of log ops, eliminating this
should be marginally better for performance. Therefore this patch
eliminates it.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>