It's a bad idea to filter bots by username

See usernames such as "Ciubotaru" and https://bugzilla.wikimedia.org/show_bug.cgi?id=56219

As I understand, there is currently no 100% reliable way of removing bots from the contributor list. However, http://www.mediawiki.org/wiki/Manual:Bots#Bot_right.2C_group.2C_and_flag offers a few pointers on how to do it as cleanly as possible.
Update test to account for bot users.