ocfs2: bump up o2cb network protocol version

Two new messages are added to support negotiating hb timeout.  Stop
nodes frmo talking an old version to mount as they will cause the
negotiation to fail.

Link: http://lkml.kernel.org/r/1464231615-27939-1-git-send-email-junxiao.bi@oracle.com
Signed-off-by: Junxiao Bi <junxiao.bi@oracle.com>
Reviewed-by: Mark Fasheh <mfasheh@suse.de>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Joseph Qi <joseph.qi@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>