config: debug message for list of missing repo names

Its useful to know the missing repos that are required to
create the full configuration as they are detected.

This might help to find problems within the configuration and kas code
in the future.

Signed-off-by: Claudius Heine <ch@denx.de>

kas/config.py

@@ -73,6 +73,9 @@ class Config:
                 raise IncludeException('Could not fetch all repos needed by '
                                        'includes.')
 
+            logging.debug('Missing repos for complete config:\n%s',
+                          pprint.pformat(missing_repo_names))
+
             repo_dict = self.get_repo_dict()
             missing_repos = [repo_dict[repo_name]
                              for repo_name in missing_repo_names