ocfs2: Bugfix for hard readonly mount

ocfs2 cannot currently mount a device that is readonly at the media
("hard readonly").  Fix the broken places.
see detail: http://oss.oracle.com/bugzilla/show_bug.cgi?id=1322

[ Description edited -- Joel ]

Signed-off-by: Tiger Yang <tiger.yang@oracle.com>
Reviewed-by: Sunil Mushran <sunil.mushran@oracle.com>
Signed-off-by: Joel Becker <jlbec@evilplan.org>