Fixing assignment/equality test error.
Fixing assignment/equality test error.

Summary: Used = when needed ==

Reviewed By: lbrandy

Differential Revision: D2817318

fb-gh-sync-id: f89442a37ee47bc060a2826708130af54c773918

Orvid/proxygen,Orvid/proxygen,Orvid/proxygen,Orvid/proxygen