Keep the IPVS hooks registered in Netfilter only
while there are configured virtual services. This
saves CPU cycles while IPVS is loaded but not used.
Signed-off-by: Julian Anastasov <ja@ssi.bg>
Reviewed-by: Simon Horman <horms@verge.net.au>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>