Fixup test.
Fixup test.

Summary: The error code is actually expected to be transport here.

Reviewed By: yangchi

Differential Revision: D20553042

fbshipit-source-id: 82eb5dd51b5b0ccddebe6a5eb9c5c723f2caa95a

facebookincubator/mvfst,facebookincubator/mvfst,facebookincubator/mvfst,facebookincubator/mvfst,facebookincubator/mvfst