remove non-root users from kaulen since it's not used as download server

RT #1839

since misc::download-mediawiki is not on this host anymore and those accounts
had been added for that, they are not needed and should instead be added
where Mediawiki is going to be downloaded from (new platform eng. download server in eqiad)

unless, one of you actually used those accounts to debug Bugzilla or other tasks

Change-Id: I198bba8006289c4235151beaf3505324b20383a7
Merge "remove non-root users from kaulen since it's not used as download server" into production