Francisco Bolanos wouldn't tell me how he makes the smoky salsa brava he dresses his fried potatoes with. Over the phone he told me it's a "family secret," though I swear he used the words "jamon stock" when he served them to me a few mornings earlier at Little Madrid Tapas Cafe, a cash-only Andersonville hole-in-the-wall that resets the standard for patatas bravas in a