vinyl: do not account bloom filters to runtime quota

Back when bloom filters were introduced, neither box.info.memory() nor
box.stat.vinyl().memory didn't exist so bloom filters were accounted to
box.runtime.info().used for lack of a better place. Now, there's no
point to account them there. In fact, it's confusing, because bloom
filters are allocated with malloc(), not from the runtime arena, so
let's drop it.