Update lib/POE/Filter/DNS/TCP.pm

The same fix as for https://github.com/bingos/poe-component-server-dns/commit/9d5facc88a8abaa052af9a23938bbf05776c1ff3 was needed here.
Merge pull request #1 from stephan48/master

Added the fix/hack needed for the UDP DNS Filter also to the TCP DNS Filter Module