A hard-won deal to keep the A's playing baseball in Oakland for another 10 years was nearly completed Tuesday when the Alameda County Board of Supervisors unanimously approved the lease agreement. All that's needed now is the formal blessing of the Oakland-Alameda County Coliseum Authority - the A's landlord - whose members are county supervisors, City Council members and their appointees. "Every incentive in this agreement is (intended) to give them incentives to stay," said Jon Streeter, an attorney for the Oakland-Alameda County Coliseum Authority. The lease agreement includes a clause shielding the city from liability, which was among the last-minute language changes inserted by the Oakland City Council during a testy meeting July 16.