fixup conn _api_versions when config set

Author: dpkp

kafka/conn.py

@@ -543,6 +543,7 @@ def _try_api_versions_check(self):
         if self._api_versions_future is None:
             if self.config['api_version'] is not None:
                 self._api_version = self.config['api_version']
+                self._api_versions = BROKER_API_VERSIONS[self._api_version]
                 return True
             elif self._check_version_idx is None:
                 request = ApiVersionsRequest[self._api_versions_idx]()