title: Emacs silently changes font when using another text encoding
body: <p>I have installed emacs25 (Kubuntu 18.04.1). I have text/tex files in Cyrillic in different encodings: utf-8 and cp1251. </p>
  
  <p>The font face for utf-8 cyryllic seems OK, just the one I set with <code>customize-face default</code>, but when I open a file in cp1251 encoding, the font face isget changed to some ugly-looking cyrillic face. </p>
  
  <p>I don't understand why this happens. How can I make it keep the same font for all cyrillic text encodings?</p>