Bug-fix: erroneously filtering vote messages by age

This bug was introduced in commit 9c91d32a 2 years ago and would result
in votes and poll message being erroneously filtered. e.g.
!Filtering QWK message from (null) due to age: 19321 days

The filter criteria was either a zero-initialized msg or the previously
parsed/imported msg from the QWK or REP packet.

A solution for filtering vote/poll messages is needed, but this isn't it.