automaintainer: stripping email tags breaks when user has tags in profile

ef554a51 strips the email tags (+) from email addresses to increase the chance of the address matching the one in the profile of the user.

Some users have these tags in their profile as well. So when the automaintainer tries to find users with the stripped e-mail address, none are found.

Solve this by searching for both the original e-mail address as the stripped version.