Avoid resource leaks

Author: tisnik

src/runners/quota_scheduler.py

@@ -95,6 +95,11 @@ def quota_scheduler(config: QuotaHandlersConfiguration) -> bool:
         for limiter in config.limiters:
             try:
                 if not connected(connection):
+                    # the old connection might be closed to avoid resource leaks
+                    try:
+                        connection.close()
+                    except Exception:  # pylint: disable=broad-exception-caught
+                        pass  # Connection already dead
                     connection = connect(config)
                     if connection is None:
                         logger.warning("Can not connect to database, skipping")