Merge branch 'net-convert-ipv6_stub-to-ip6_dst_lookup_flow'

Sabrina Dubroca says:

====================
net: convert ipv6_stub to ip6_dst_lookup_flow

Xiumei Mu reported a bug in a VXLAN over IPsec setup:

  IPv6 | ESP | VXLAN

Using this setup, packets go out unencrypted, because VXLAN over IPv6
gets its route from ipv6_stub->ipv6_dst_lookup (in vxlan6_get_route),
which doesn't perform an XFRM lookup.

This patchset first makes ip6_dst_lookup_flow suitable for some
existing users of ipv6_stub->ipv6_dst_lookup by adding a 'net'
argument, then converts all those users.
====================

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