Editing PR (revoking issue reference) doesn't remove open claim on SOB

[churik]

Description

Type: Bug
Summary: if PR title/comment (which already is a claim on bounty x) is edited in order to make the new claim to another bounty (i.e. Fixes #x is replaced by Fixes #y or Fixes #non-existing_issue) or even deleted - it is still displayed as open claim on bounty x

Expected behavior

no open claims

Actual behavior

nothing changed

Reproduction

Requirements: GH account is whitelisted, signed app, test application is added to repo;

• create an issue with bounty in https://openbounty.status.im:444/app#/
• create PR to fix it (i.e. (fixes #issue)
• open PR on GitHub
• delete the comment with fixes #issue
• go to Open bounties, pay attention to open claims amount

Additional Information

• Video: http://take.ms/Shcyz

• Browser: Chrome

• Operating System: Mac OS High Sierra