Don't throw when deserializing partial headers
Don't throw when deserializing partial headers

Summary: Title.

Reviewed By: spalamarchuk

Differential Revision: D5150401

fbshipit-source-id: 7c8dfdb2ca649e6bf2880114a3d1c18da126e855

facebook/mcrouter,facebook/mcrouter,facebook/mcrouter,facebook/mcrouter