[Fix] Prevent DNSWL sabotage

[Fix] Prevent DNSWL sabotage

When exceeding the query limit for DNSWL it can happen that instead
of the returncode 127.0.0.255, that according to documentation
(https://www.dnswl.org/?page_id=15) indicates a block, the
returncode 127.0.10.3 is returned for all queries.

According to documentation (https://www.dnswl.org/?page_id=15) the
127.0.10.3 returncode indicates the highest level of trustworthiness
that should never be blocked and a category of 'some special cases'.

As it turns out that documentation is a lie and that 127.0.10.3
returncode is used by DNSWL to intentionally sabotage email security
by marking all sending servers as highly trustworthy
(https://www.dnswl.org/?p=120).