folly/futures/test/NonCopyableLambdaTest.cpp: avoid shadowing warnings
folly/futures/test/NonCopyableLambdaTest.cpp: avoid shadowing warnings

Summary: Fix warnings exposed by the upstream-proposed -Wshadow-compatible-local option.

Reviewed By: markisaa

Differential Revision: D4041764

fbshipit-source-id: b2aa6543ce4bc36069b010f1107f1ac117073b26

Orvid/folly,Orvid/folly,charsyam/folly,rklabs/folly,charsyam/folly,rklabs/folly,floxard/folly,facebook/folly,Orvid/folly,Orvid/folly,facebook/folly,facebook/folly,rklabs/folly,charsyam/folly,facebook/folly,facebook/folly,floxard/folly,floxard/folly,floxard/folly,Orvid/folly,charsyam/folly,rklabs/folly,floxard/folly,rklabs/folly