Unify recv window logging for Proxygen clients
Unify recv window logging for Proxygen clients

Summary:
We weren't logging the flow control window for QUIC connections, which
doesn't help investigating rageshakes.

Reviewed By: JunqiWang

Differential Revision: D24520360

fbshipit-source-id: d13aa9e69b214b8700ce0e1295b15d0504fdff7e

facebook/wangle,facebook/wangle,facebook/wangle