bug#21235: emacs 24.4.1 pollutes terminal when it cannot save #file#

[Askar Safin]

Steps to reproduce:
1. You should have some directory where you cannot write (for example, you are 
user "user" and you cannot write to "/").
And you should have some file in this directory you able to write. For example:
$ sudo touch /file
$ sudo chown user:user /file
$ emacs -nw /file
2. Type some text to file, then press C-x C-c, then press "n" (i. e. "don't 
save"), then type "yes" (i. e. "exit anyway")

You will see this message:
"Auto-saving file: Opening output file: permission denied, /#file#"

And then your terminal will be somehow destroyed/polluted. For example, Emacs 
image will continue to exists in your
terminal, even if it normally doesn't do this. Or alternatively, new prompt 
will appear on top of error message and you
will see, for example, this:

15  2015-08-11 11:54:04  ~$ emacs /file
Auto-sav15  2015-08-11 11:54:13  ~$ e: permission denied, /#file#

Emacs 24.4.1, all this happened in Konsole (sic!) 2.14.2, KDE 4.14.2, Debian 
GNU/Linux Jessie 8.

==
Askar Safin
http://vk.com/safinaskar