bug: ctl: list_queues JSON: ignore source queues of collectors

as collectors don't have source queues, don't report any (always zero)
size for their source queues.
This was introduced with the rewrite to the
pipeline-runtime-configuration merge, as the source queues got default
values, independent if they are useful or not

intelmq/bin/intelmqctl.py

@@ -1331,7 +1331,10 @@ def list_queues(self, non_zero=False, count=False):
             for bot_id, info in self._pipeline_configuration().items():
                 return_dict[bot_id] = {}
 
-                if 'source_queue' in info:
+                # Do not report source queues for collectors
+                if 'source_queue' in info and not (
+                        self.runtime_configuration[bot_id].get('group', None) == 'Collector' or
+                        self.runtime_configuration[bot_id].get('groupname', None) == 'collectors'):
                     return_dict[bot_id]['source_queue'] = (
                         info['source_queue'], counters[info['source_queue']])
                     if pipeline.has_internal_queues: