netlink_delinearize: incorrect meta protocol dependency kill again

netlink_delinearize: incorrect meta protocol dependency kill again

This patch adds __meta_dependency_may_kill() to consolidate inspection
of the meta protocol, nfproto and ether type expression to validate
dependency removal on listings.

Phil reports that 567ea4774e13 includes an update on the ip and ip6
families that is not described in the patch, moreover, it flips the
default verdict from true to false.

Fixes: 567ea4774e13 ("netlink_delinearize: incorrect meta protocol dependency kill")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>