[hack] refactor -- explicitly bail in inner loop of hh_collect on deleted keys.
[hack] refactor -- explicitly bail in inner loop of hh_collect on deleted keys.

Summary: explicitly bail inside `hh_collect` if we found an explicitly deleted key. It is not a candidate for replacement.

Reviewed By: alexchow

Differential Revision: D7775902

fbshipit-source-id: 3d5ba54a85710ecc154d8eea02a6b4b35e2689fb

samwgoldman/flow,gabelevi/flow,samwgoldman/flow,popham/flow,JonathanUsername/flow,nmote/flow,JonathanUsername/flow,AgentME/flow,facebook/flow,JonathanUsername/flow,AgentME/flow,jamesgpearce/flow,gabelevi/flow,AgentME/flow,facebook/flow,nmote/flow,jamesgpearce/flow,facebook/flow,samwgoldman/flow,mroch/flow,nmote/flow,samwgoldman/flow,claudiopro/flow,mroch/flow,AgentME/flow,nmote/flow,jamesgpearce/flow,jamesgpearce/flow,mroch/flow,JonathanUsername/flow,gabelevi/flow,popham/flow,JonathanUsername/flow,facebook/flow,popham/flow,claudiopro/flow,jamesgpearce/flow,mroch/flow,samwgoldman/flow,popham/flow,nmote/flow,samwgoldman/flow,facebook/flow,nmote/flow,samwgoldman/flow,popham/flow,claudiopro/flow,claudiopro/flow,popham/flow,popham/flow,JonathanUsername/flow,JonathanUsername/flow,mroch/flow,claudiopro/flow,jamesgpearce/flow,gabelevi/flow,facebook/flow,facebook/flow,AgentME/flow,jamesgpearce/flow,gabelevi/flow,nmote/flow,gabelevi/flow,gabelevi/flow,mroch/flow,mroch/flow