igmp: Avoid zero delay when receiving odd mixture of IGMP queries

Commit 5b7c84066733c5dfb0e4016d939757b38de189e4 ('ipv4: correct IGMP
behavior on v3 query during v2-compatibility mode') added yet another
case for query parsing, which can result in max_delay = 0.  Substitute
a value of 1, as in the usual v3 case.

Reported-by: Simon McVittie <smcv@debian.org>
References: http://bugs.debian.org/654876
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
	__releases(rcu)
{
	struct igmp_mcf_iter_state *state = igmp_mcf_seq_private(seq);
	if (likely(state->im != NULL)) {
		spin_unlock_bh(&state->im->lock);
		state->im = NULL;
	}
	state->idev = NULL;
	state->dev = NULL;
	rcu_read_unlock();
}

	__releases(rcu)
{
	struct igmp_mcf_iter_state *state = igmp_mcf_seq_private(seq);
	if (likely(state->im != NULL)) {
		spin_unlock_bh(&state->im->lock);
		state->im = NULL;
	}
	state->idev = NULL;
	state->dev = NULL;
	rcu_read_unlock();
}
