Lupe Garcia, mayor of Livingston in Merced County, is snapping at a new state law that overturns his city's ordinance banning pit bulldogs. Prodded by dog owners, the Legislature passed and Gov. Deukmejian signed a bill that prevents local authorities from barring specific breeds of dogs. Other cities and counties concerned by reports of maulings, some fatal, took a broader approach by banning vicious dogs, but not specifically pit bulls. "We have to do something to protect our people from pit bulls," Garcia said. "They're unpredictable, dangerous killers, and they shouldn't be on the street."