make ext3 mount default to barrier=1

From 00eacd66cd8ab5fff9df49aa3f261ad43d495434 Mon Sep 17 00:00:00 2001
From: Christoph Hellwig <hch@infradead.org>
Date: Sat, 16 Jul 2011 16:46:50 -0400

This patch turns on barriers by default for ext3.  mount -o barrier=0
will turn them off.  Based on a patch from Chris Mason in the SuSE tree.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Eric Sandeen <sandeen@redhat.com>
Acked-by: Jan Kara <jack@suse.cz>
Acked-by: Jeff Mahoney <jeffm@suse.com>
Acked-by: Ted Ts'o <tytso@mit.edu>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>