Bug#839008: scribus no longer finds DejaVu fonts

[Hartmut Buhrmester]

Apparently, this is caused by a bug in the FreeType library 
libfreetype6. An upstream bug report says:

This is a bug caused by some FreeType versions which fail when loading
some glyphs outlines and make us consider some fonts as broken. At
least FreeType 2.6.0 to 2.6.3 are affected. FreeType 2.6.5 was
fixed. Unfortunately Debian 9 has FreeType 2.6.3. If you upgrade
FreeType to >= 2.6.5, you will have to clear scribus font cache.

- https://bugs.scribus.net/view.php?id=15042