Permits revocable at the will of the commission for such minor or temporary public utility privileges as may be specified by general ordinance may be granted and revoked by the commission from time to time in accordance with the terms and conditions to be prescribed thereby; and such permits shall not be deemed to be franchises as the term is used in this Charter. Such general ordinance, however, shall be subject to the same procedure as an ordinance granting a franchise and shall not be passed as an emergency measure.