Move xplat/rsocket from autosyncer to dirsync
Move xplat/rsocket from autosyncer to dirsync

Summary:
* remove rsocket from autosyncer
* set up dirsync for rsocket
* mirror source file for xplat/rsocket fbcode/rsocket

Reviewed By: jmswen

Differential Revision: D16183718

fbshipit-source-id: ab130be29228989748ccb931259d0b876425a8e6

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