Issue #288: Repo admin should be allowed to delete PR (conservancy/kallithea)

[Long Vu]

New issue 288: Repo admin should be allowed to delete PR
https://bitbucket.org/conservancy/kallithea/issues/288/repo-admin-should-be-allowed-to-delete-pr

Long Vu:

Right now, only the PR owner see the "delete" button in the list of PR for a given repo.

The repo admin should also have access to that delete button to delete broken PR (ex: when a PR has accidentally created with wrong source and destination resulting in a gigantic diff that takes a lot of time to render the PR to the browser).

See thread on the mailing list https://lists.sfconservancy.org/pipermail/kallithea-general/2017q3/002393.html