The modified patch looks OK to me and tests OK.  The rl_read_init_file call seems like a reasonable thing for users who are used to using libedit's .editrc.  As a practical matter, though, I think the only thing that would be affected is an .editrc TAB binding.  Some of the initializations done in Modules/readline.c, like rl_bind_key_in_map (for sure) and rl_completer_word_break_characters are silently ignored by the libedit readline-compatibility layer; it does not implement features like the emacs_meta_keymap.