[py] add a more descriptive log message if the port cannot be connected

fixes #2913

Author: lmtierney

py/selenium/webdriver/remote/remote_connection.py

@@ -200,6 +200,10 @@ def __init__(self, remote_server_addr, keep_alive=False, resolve_ip=True):
             port = parsed_url.port or None
             if parsed_url.scheme == "https":
                 ip = parsed_url.hostname
+            elif port and not common_utils.is_connectable(port, parsed_url.hostname):
+                ip = None
+                LOGGER.info('Could not connect to port {} on host '
+                            '{}'.format(port, parsed_url.hostname))
             else:
                 ip = common_utils.find_connectable_ip(parsed_url.hostname,
                                                       port=port)