Fixes 500 error on dashboard when using MSSQL (#2504)

Fixes 500 error on dashboard when using MSSQL (#2504)

MSSQL rejects the query:
  SELECT "repository"."id" FROM "repository"
  INNER JOIN "team_repo" ON "team_repo".repo_id="repository".id AND
  "repository".is_mirror=1
  WHERE (
    ("repository".owner_id=2 AND "repository".is_private=0)
        OR team_repo.team_id IN (1)
        )
        GROUP BY "repository".id ORDER BY updated_unix DESC

when the order by term (updated_unix) is not included in the group by
term.