Update clang plugin
Update clang plugin

Summary: public
Update plugin. Change:
- ConstrutorExpr exports decl_ref of ConstructorDecl instead of just pointer to the declaration

Reviewed By: dulmarod

Differential Revision: D2569978

fb-gh-sync-id: ebc687f

ryoon/infer,jvillard/infer,blzq/infer,jvillard/infer,kageiit/infer,facebook/infer,kstreee/infer,ropas/infer,ryoon/infer,ryoon/infer,kageiit/infer,blzq/infer,kageiit/infer,kstreee/infer,xennygrimmato/infer,jsachs/infer,xennygrimmato/infer,jvillard/infer,jvillard/infer,jvillard/infer,jsachs/infer,facebook/infer,facebook/infer,jvillard/infer,xennygrimmato/infer,kstreee/infer,facebook/infer,jsachs/infer,facebook/infer,blzq/infer,ryoon/infer,kageiit/infer,facebook/infer,facebook/infer,kageiit/infer,xennygrimmato/infer,xennygrimmato/infer,jsachs/infer,ryoon/infer,kageiit/infer,jsachs/infer,kageiit/infer,xennygrimmato/infer,ropas/infer,kstreee/infer,ropas/infer,ropas/infer,kstreee/infer,blzq/infer,jsachs/infer,blzq/infer,xennygrimmato/infer,ryoon/infer,ropas/infer,jvillard/infer,blzq/infer,ropas/infer,kstreee/infer