netfilter: nf_tables: check if catch-all set element is active in next generation

When deactivating the catch-all set element, check the state in the next
generation that represents this transaction.

This bug uncovered after the recent removal of the element busy mark
a2dd0233 ("netfilter: nf_tables: remove busy mark and gc batch API").

Fixes: aaa31047 ("netfilter: nftables: add catch-all set element support")
Cc: stable@vger.kernel.org
Reported-by: lonial con <kongln9170@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>