ocfs2/dlm: Use negotiated o2dlm protocol version

Patch fixes a bug in the o2dlm protocol negotiation in that it is using
the builtin version rather than the negotiated version during the domain
join. This causes join errors when a node having kernel >= 2.6.37 joins
a cluster with nodes having kernels < 2.6.37.

This only affects the o2cb cluster stack.

Signed-off-by: Sunil Mushran <sunil.mushran@oracle.com>
Reported-by: Jacek Stepniewski <Jacek.Stepniewski@agora.pl>
Acked-by: Mark Fasheh <mfasheh@suse.com>
Signed-off-by: Joel Becker <jlbec@evilplan.org>