Revert "ocfs2: bump up o2cb network protocol version"

This reverts commit 38b52efd ("ocfs2: bump up o2cb network protocol
version").

This commit made rolling upgrade fail.  When one node is upgraded to new
version with this commit, the remaining nodes will fail to establish
connections to it, then the application like VMs on the remaining nodes
can't be live migrated to the upgraded one.  This will cause an outage.
Since negotiate hb timeout behavior didn't change without this commit,
so revert it.

Fixes: 38b52efd

 ("ocfs2: bump up o2cb network protocol version")
Link: http://lkml.kernel.org/r/1471396924-10375-1-git-send-email-junxiao.bi@oracle.com
Signed-off-by: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Mark Fasheh <mfasheh@suse.de>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Joseph Qi <joseph.qi@huawei.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>