[GFS2] Revert part of earlier log.c changes

This is patch 2 of 5 for bug #248176.

The list_move code previously concocted in log.c for bug #238162
(see https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=238162#c23

)
never runs as bh can now never be NULL at this point.

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