Suppress -Wshadow for SYNCHRONIZED
Suppress -Wshadow for SYNCHRONIZED

Summary: SYNCHRONIZED warns with -Wshadow due to `for (auto&
FB_ARG_1(__VA_ARGS__) =`. This diff just suppresses that warning.

Reviewed By: djwatson

Differential Revision: D2587348

fb-gh-sync-id: 3a2e39fb6ce28da014950ca94e4b62ea80deb65f

facebook/folly,floxard/folly,brunomorishita/folly,Orvid/folly,charsyam/folly,rklabs/folly,Orvid/folly,Hincoin/folly,gaoyingie/folly,floxard/folly,mqeizi/folly,rklabs/folly,gaoyingie/folly,floxard/folly,mqeizi/folly,facebook/folly,brunomorishita/folly,rklabs/folly,floxard/folly,mqeizi/folly,alexst07/folly,Orvid/folly,Orvid/folly,brunomorishita/folly,facebook/folly,sonnyhu/folly,floxard/folly,mqeizi/folly,Orvid/folly,sonnyhu/folly,charsyam/folly,gaoyingie/folly,brunomorishita/folly,Hincoin/folly,juniway/folly,Hincoin/folly,gaoyingie/folly,rklabs/folly,alexst07/folly,sonnyhu/folly,facebook/folly,sonnyhu/folly,juniway/folly,sonnyhu/folly,rklabs/folly,brunomorishita/folly,charsyam/folly,alexst07/folly,Hincoin/folly,Hincoin/folly,juniway/folly,juniway/folly,charsyam/folly,juniway/folly,facebook/folly,alexst07/folly,gaoyingie/folly,mqeizi/folly,alexst07/folly