By OLGA R. RODRIGUEZ and HAVEN DALEY HALF MOON BAY (AP) — A migrant farmworker who survived a mass shooting last year at a Northern California mushroom farm has filed a lawsuit against the farm and one of its owners, saying they failed to keep him safe from the colleague who authorities say committed the killings, the worker and his attorneys said Friday. Pedro Romero Perez, 24, was in the shipping container that served as his and his brother’s…