bug#25612: 26.0.50; Slightly suboptimal message for disabled commands

[Eli Zaretskii]

> From: Philipp Stephani <p.stephani2@gmail.com>
> Date: Fri, 03 Feb 2017 14:15:30 +0000
> Cc: 25612@debbugs.gnu.org
> 
>  Perhaps the message should avoid showing the key sequence at all?
> 
> It seems that this is the intention of lines 54 through 62 in novice.el, but 
> it doesn't seem to work any more.

Indeed.

> This is a regression: it still works as expected in Emacs 23.4, but no longer 
> in Emacs 24.3. Probably
> something about this-command-keys or command-execute changed in the meantime 
> so that the code in
> novice.el no longer works as expected.

Yes, this-command-keys returns just "^M" instead of the expected
"\370erase-buffer^M" it returned in Emacs 24.2 and older.