fd00ef394e
Replace some uses with folly functions or boost. I kept string_vsnprintf in its own header for now. We could probably move it to folly/String.h (folly has stringPrintf and such, just no vararg version), but on the other hand using va_list is not very encouraged so maybe we should just leave it here for these legacy uses. Reviewed By: @ptarjan Differential Revision: D1124742