netfilter: auto-load ip6_queue module when socket opened

The ip6_queue module is missing the net-pf-16-proto-13 alias that would
cause it to be auto-loaded when a socket of that type is opened.  This
patch adds the alias.

Signed-off-by: Scott James Remnant <scott@canonical.com>
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>
Signed-off-by: Patrick McHardy <kaber@trash.net>