mononoke: make metaconfig OSS buildable
mononoke: make metaconfig OSS buildable

Summary: This diff makes it possible to relay on the thrift structures from configerator in OSS.

Reviewed By: ahornby

Differential Revision: D20279457

fbshipit-source-id: 39df1c7a6f78b10a0a5bdeeebe476249ab674cc8

ReactiveSocket/reactivesocket-cpp,ReactiveSocket/reactivesocket-cpp,rsocket/rsocket-cpp,rsocket/rsocket-cpp,ReactiveSocket/reactivesocket-cpp,rsocket/rsocket-cpp,rsocket/rsocket-cpp