gfs2: Get rid of gfs2_glock_queue_put in signal_our_withdraw

In function signal_our_withdraw(), we are calling gfs2_glock_queue_put()
in a context in which we are actually allowed to sleep, so replace that
with a simple call to gfs2_glock_put().

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>