Only leave a comment when no more pending CI (GH-28)

- Ensure travis job has kicked off before checking for `pending` status.

backport/status_change.py

@@ -26,8 +26,12 @@ async def check_status(event, gh, *args, **kwargs):
         response = requests.get(status_url,
                                  headers=request_headers)
         result = response.json()
-        print(f"miss-islington's PR state changed: {result['state']}")
-        if result["state"] != "pending":
+        all_ci_status = [status["state"] for status in result["statuses"]]
+        all_ci_context = [status["context"] for status in result["statuses"]]
+        print(f"miss-islington's PR state changed: {all_ci_status}")
+        print(f"miss-islington's PR CI: {all_ci_context}")
+        if "pending" not in all_ci_status \
+                and "continuous-integration/travis-ci/pr" in all_ci_context:
             url = "https://api.github.com/repos/miss-islington/cpython/git/refs/heads/"
             response = requests.get(url, headers=request_headers)
             for ref in response.json():