message: tear down java2 (part 1/n)
  Summary: now that we successfully merged java and java2 thrift compilers, we no longer need extra java2 thrift libraries.
diff: namespace java com.facebook.fb303.core
  namespace java.swift com.facebook.swift.fb303.core
  -namespace java2 com.facebook.thrift.fb303.core
  namespace cpp facebook.fb303
  namespace py.asyncio fb303_asyncio.fb303_core
  namespace perl fb303
  