Fix visibility of service users for non-admin owners

Owners of service users that were not admins weren't able to see their
service users. Gerrit was searching for the owner using the account id
of the service user, but the data was stored using the username instead.
Thus, Gerrit was unable to find the owner.

Change-Id: I9e2bc89d89bd50079b45796bca860a67139858ed
1 file changed