remove unused header
remove unused header

Summary: ^

Reviewed By: sharma95

Differential Revision: D15226868

fbshipit-source-id: c8090ed93e2d0d9c9092fcdfdc34698ff824c334

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