ipvs: Pass ipvs not net to ip_vs_svc_hashkey

Use the address of ipvs not the address of net when computing the
hash value.  This removes an unncessary dependency on struct net.

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>