netfilter: nf_tables: Drop dead code from fill_*_info routines

This practically reverts commit 28339b21 ("netfilter: nf_tables: do
not send complete notification of deletions"): The feature was never
effective, due to prior modification of 'event' variable the conditional
early return never happened.

User space also relies upon the current behaviour, so better reintroduce
the shortened deletion notifications once it is fixed.

Fixes: 28339b21 ("netfilter: nf_tables: do not send complete notification of deletions")
Signed-off-by: Phil Sutter <phil@nwl.cc>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>