__inet_hash_connect() does not use its third argument (port_offset)
if socket was already bound to a source port.

No need to perform useless but expensive md5 computations.
Reported-by: NCrestez Dan Leonard <cdleonard@gmail.com>
Signed-off-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>