use python3-compatible prints

synapse/config/_base.py

@@ -288,22 +288,22 @@ class Config(object):
                     )
                     obj.invoke_all("generate_files", config)
                     config_file.write(config_bytes)
-                print (
+                print((
                     "A config file has been generated in %r for server name"
                     " %r with corresponding SSL keys and self-signed"
                     " certificates. Please review this file and customise it"
                     " to your needs."
-                ) % (config_path, server_name)
+                ) % (config_path, server_name))
                 print(
                     "If this server name is incorrect, you will need to"
                     " regenerate the SSL certificates"
                 )
                 return
             else:
-                print (
+                print((
                     "Config file %r already exists. Generating any missing key"
                     " files."
-                ) % (config_path,)
+                ) % (config_path,))
                 generate_keys = True
 
         parser = argparse.ArgumentParser(