Pylint: enable global-variable-not-assigned check

the global keyword should be used only when variable from outside is
assigned inside, otherwise it has no effect and just confuses developers

Reviewed-By: Tomas Krizek <tkrizek@redhat.com>

install/tools/ipa-replica-conncheck

@@ -385,7 +385,6 @@ def main():
         print_info("\nConnection from replica to master is OK.")
 
         # create listeners
-        global RESPONDERS
         print_info("Start listening on required ports for remote master check")
 
         for port in required_ports: