[FIX] *: better cope with secondary rate limits

* the repository apparently takes a lot more time to
  propagate (randomly) now, so wait until we can *see* it
* also add sleep after modification operations on the new repository

Ideally this should be done a lot more ubiquitously, but for now this
seems to more or less suffice.

conftest.py

@@ -403,6 +403,13 @@ def make_repo(capsys, request, config, tunnel, users):
             # 'allow_merge_commit': False,
             'allow_rebase_merge': False,
         }))
+        r = r.json()
+        # wait for repository visibility
+        while True:
+            time.sleep(1)
+            if github.head(r['url']).ok:
+                break
+
         repo = Repo(github, fullname, repos)
 
         # create webhook
@@ -415,6 +422,7 @@ def make_repo(capsys, request, config, tunnel, users):
             },
             'events': ['pull_request', 'issue_comment', 'status', 'pull_request_review']
         }))
+        time.sleep(1)
 
         check(github.put('{}/contents/{}'.format(repo_url, 'a'), json={
             'path': 'a',
@@ -422,8 +430,7 @@ def make_repo(capsys, request, config, tunnel, users):
             'content': base64.b64encode(b'whee').decode('ascii'),
             'branch': 'garbage_%s' % uuid.uuid4()
         }))
-        # try to unwatch repo, doesn't actually work
-        repo.unsubscribe()
+        time.sleep(1)
         return repo
 
     yield repomaker