inet: Fix virt-manager regression due to bind(0) changes.

inet: Fix virt-manager regression due to bind(0) changes.

From: Stephen Hemminger <shemminger@vyatta.com>

Fix regression introduced by 4b00edfcd96c24348e98f0f17fe6c51963612c19
("inet: Allowing more than 64k connections and heavily optimize
bind(0) time.")

Based upon initial patches and feedback from Evegniy Polyakov and
Eric Dumazet.

From Eric Dumazet:
--------------------
Also there might be a problem at line 175

if (sk->sk_reuse && sk->sk_state != TCP_LISTEN && --attempts >= 0) {
	spin_unlock(&head->lock);
	goto again;

If we entered inet_csk_get_port() with a non null snum, we can "goto again"
while it was not expected.
--------------------

Signed-off-by: David S. Miller <davem@davemloft.net>