Improve cyrus-imap (and pop) filter

Apparently we had a regression, which was caught when I have pushed a security update into wheezy
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=755173
So the first commit should address that (allow for imaps and pop3s) and should be cherry picked into 0.8 (and Debian wheezy patches), and 2nd one adds "user not found" entries to be caught as a new enhancement.