[IMP] runbot_merge: logging of gh requests

The loggers would only print the "tail" of the path, not including the
repo name, or the `/repos` prefix.

While this made logs shorter, it was not intentional and made
debugging some issues on endpoints harder than necessary as the calls
had to be adjusted mentally, which is completely unnecessary.

runbot_merge/github.py

@@ -105,12 +105,8 @@ class GH(object):
         """
         :type check: bool | dict[int:Exception]
         """
-        r = self._session.request(
-            method,
-            '{}/repos/{}/{}'.format(self._url, self._repo, path),
-            params=params,
-            json=json
-        )
+        path = f'/repos/{self._repo}/{path}'
+        r = self._session.request(method, self._url + path, params=params, json=json)
         self._log_gh(_gh, method, path, params, json, r)
         if check:
             if isinstance(check, collections.abc.Mapping):