OAKLAND — A mayor seeking a third consecutive term will face a challenger who says the city should expand police and bus services and lower water rates. Monte Waller, 44, hopes to unseat Mayor Bette Keehley in the Nov. 6 election. A veteran who served in the Persian Gulf War, Waller said he is running for mayor because he believes officials are mismanaging city funds. Waller, a political newcomer, said he wants the city to establish its own police department and ensure U-Trans extends bus service to the North County town of just fewer than 1,000 residents. Oakland residents pay …