Remove reference to the old commands file

Commands aren't stored in a special file anymore, and Kaylee never tries
to look at that file.  Therefore, there's no need for the Config object
to keep that file's path, and so the path has been removed.

kayleevc/util.py

     data_dir = os.path.join(GLib.get_user_data_dir(), program_name)
 
     # Configuration files
-    command_file = os.path.join(conf_dir, "commands.conf")
     opt_file = os.path.join(conf_dir, "options.json")
 
     # Cache files