ipvs: Pass ipvs not net to ip_vs_conn_hashkey

Use the address of struct netns_ipvs in the hash not the address of
struct net.  Both addresses are equally valid candidates and by using
the address of struct netns_ipvs there becomes no need deal with
struct net in this part of the code.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Acked-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Simon Horman <horms@verge.net.au>