Remove useless code.

The routine was originaly used in code for resetting default
argument values. It was used in cli plugins related code
where we needed to parse command line arguments twice.

src/cryptsetup.c

@@ -52,8 +52,6 @@ void tools_cleanup(void)
 		free(keyfiles[--keyfiles_count]);
 
 	total_keyfiles = 0;
-
-	args_reset_default_values(tool_core_args);
 }
 
 static const char *uuid_or_device_header(const char **data_device)