[hack] Silence some warnings for OSS build with 4.03
[hack] Silence some warnings for OSS build with 4.03

Summary:
Silences warnings for `third-party/core/result.ml` usage of `Ok` and `Error` which shadow those variants from the prelude (we rename elsewhere but I didn't want to do that to third-party code), and a warning about matching an exact error string from an exception.

Ref. https://github.com/facebook/hhvm/issues/7040

Reviewed By: gabelevi

Differential Revision: D3310203

fbshipit-source-id: aa8ec7585797b04a90f31847f725dc99458584bc

TiddoLangerak/flow,popham/flow,jamesgpearce/flow,AprilArcus/flow,jgrund/flow,cesarandreu/flow,jdelStrother/flow,gabelevi/flow,mroch/flow,jdelStrother/flow,fletcherw/flow,TiddoLangerak/flow,mroch/flow,TiddoLangerak/flow,gabro/flow,popham/flow,gabelevi/flow,ylu1317/flow,gabro/flow,ForbesLindesay/flow,nmote/flow,claudiopro/flow,facebook/flow,claudiopro/flow,AprilArcus/flow,jamesgpearce/flow,JonathanUsername/flow,AgentME/flow,cesarandreu/flow,facebook/flow,gabelevi/flow,jeffmo/flow,jdelStrother/flow,ylu1317/flow,mroch/flow,jeffmo/flow,nmote/flow,popham/flow,facebook/flow,JonathanUsername/flow,mroch/flow,JonathanUsername/flow,jeffmo/flow,samwgoldman/flow,MichaelDeBoey/flow,samwgoldman/flow,ForbesLindesay/flow,gabelevi/flow,AgentME/flow,claudiopro/flow,jdelStrother/flow,JonathanUsername/flow,fletcherw/flow,facebook/flow,claudiopro/flow,samwgoldman/flow,fletcherw/flow,mroch/flow,jgrund/flow,gabelevi/flow,gabelevi/flow,nmote/flow,chenglou/flow,ForbesLindesay/flow,ylu1317/flow,popham/flow,mroch/flow,chenglou/flow,AprilArcus/flow,jdelStrother/flow,cesarandreu/flow,fletcherw/flow,chenglou/flow,gabro/flow,nmote/flow,nmote/flow,jdelStrother/flow,jeffmo/flow,nmote/flow,AgentME/flow,gabro/flow,TiddoLangerak/flow,nmote/flow,chenglou/flow,AprilArcus/flow,jamesgpearce/flow,JonathanUsername/flow,samwgoldman/flow,cesarandreu/flow,AprilArcus/flow,jamesgpearce/flow,chenglou/flow,fletcherw/flow,MichaelDeBoey/flow,popham/flow,jamesgpearce/flow,JonathanUsername/flow,gabro/flow,facebook/flow,fletcherw/flow,jeffmo/flow,ForbesLindesay/flow,TiddoLangerak/flow,jeffmo/flow,jgrund/flow,AgentME/flow,ForbesLindesay/flow,claudiopro/flow,samwgoldman/flow,jamesgpearce/flow,AgentME/flow,mroch/flow,AprilArcus/flow,MichaelDeBoey/flow,ForbesLindesay/flow,gabro/flow,gabelevi/flow,jamesgpearce/flow,MichaelDeBoey/flow,ylu1317/flow,MichaelDeBoey/flow,jgrund/flow,jgrund/flow,ylu1317/flow,chenglou/flow,JonathanUsername/flow,samwgoldman/flow,facebook/flow,samwgoldman/flow,popham/flow,jgrund/flow,facebook/flow,popham/flow