xfs: do exact log space wakeups in xlog_ungrant_log_space

The only reason that xfs_log_space_wake had to do opportunistic wakeups
was that the old xfs_log_move_tail calling convention didn't allow for
exact wakeups when not updating the log tail LSN.  Since this issue has
been fixed we can do exact wakeups now.
Reviewed-by: NMark Tinguely <tinguely@sgi.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NDave Chinner <dchinner@redhat.com>
Signed-off-by: NBen Myers <bpm@sgi.com>

fs/xfs/xfs_log.c

@@ -2748,7 +2748,7 @@ xlog_ungrant_log_space(xlog_t	     *log,
 
 	trace_xfs_log_ungrant_exit(log, ticket);
 
-	xfs_log_space_wake(log->l_mp, true);
+	xfs_log_space_wake(log->l_mp, false);
 }
 
 /*