Problem trying to close PR (422: UnprocessableEntity)

[jdigger]

I suspect it has to do with the PR being closed out from underneath it by the push.

Pushing chi-7729-ping-cache to 'checkout-master' on 'origin'.
Looking for a pull request asking for 'chi-7729-ping-cache' to be merged into 'checkout-master' on webcms/omega.
Closing a pull request #1392 on webcms/omega.
Retrying closing a pull request #1392 on webcms/omega - try #2
Retrying closing a pull request #1392 on webcms/omega - try #3
Retrying closing a pull request #1392 on webcms/omega - try #4
Retrying closing a pull request #1392 on webcms/omega - try #5
Retrying closing a pull request #1392 on webcms/omega - try #6
/usr/local/opt/rbenv/versions/1.8.7-p358/lib/ruby/gems/1.8/gems/octokit-1.25.0/lib/faraday/response/raise_octokit_error.rb:22:in `on_complete': PATCH https://github.webapps.rr.com/api/v3/repos/webcms/omega/pulls/1392: 422: Validation Failed:  (Octokit::UnprocessableEntity)
    from /usr/local/opt/rbenv/versions/1.8.7-p358/lib/ruby/gems/1.8/gems/faraday-0.8.8/lib/faraday/response.rb:9:in `call'
    from /usr/local/opt/rbenv/versions/1.8.7-p358/lib/ruby/gems/1.8/gems/faraday-0.8.8/lib/faraday/response.rb:63:in `on_complete'
    from /usr/local/opt/rbenv/versions/1.8.7-p358/lib/ruby/gems/1.8/gems/faraday-0.8.8/lib/faraday/response.rb:8:in `call'
    from /usr/local/opt/rbenv/versions/1.8.7-p358/lib/ruby/gems/1.8/gems/faraday_middleware-0.9.0/lib/faraday_middleware/request/encode_json.rb:23:in `call'
    from /usr/local/opt/rbenv/versions/1.8.7-p358/lib/ruby/gems/1.8/gems/faraday-0.8.8/lib/faraday/connection.rb:253:in `run_request'
    from /usr/local/opt/rbenv/versions/1.8.7-p358/lib/ruby/gems/1.8/gems/faraday-0.8.8/lib/faraday/connection.rb:118:in `patch'
    from /usr/local/opt/rbenv/versions/1.8.7-p358/lib/ruby/gems/1.8/gems/octokit-1.25.0/lib/octokit/request.rb:65:in `send'
    from /usr/local/opt/rbenv/versions/1.8.7-p358/lib/ruby/gems/1.8/gems/octokit-1.25.0/lib/octokit/request.rb:65:in `request'
    from /usr/local/opt/rbenv/versions/1.8.7-p358/lib/ruby/gems/1.8/gems/octokit-1.25.0/lib/octokit/request.rb:25:in `patch'
    from /usr/local/opt/rbenv/versions/1.8.7-p358/lib/ruby/gems/1.8/gems/git-process-lib-2.0.2/lib/git-process/github_pull_request.rb:153:in `send_close_req'
    from /usr/local/opt/rbenv/versions/1.8.7-p358/lib/ruby/gems/1.8/gems/git-process-lib-2.0.2/lib/git-process/github_pull_request.rb:159:in `send_close_req'