Comment 3 for bug 704835

dbus gets installed again if you temporarily delete user "messagebus" out of "/etc/passwd"; but new "messagebus" gets a different UID. To repair the system you should synchronize the UIDs over all the filesystem.
It would be the better way to patch the configure-script of package dbus to not add a new user in case of update (add only on new installation) or to ignore the error return of useradd in case of pe-existence of the user to add!