Install dejavu fonts

PHP Fatal error:  SetFontTTF: Can't find TrueType font
/usr/share/fonts/truetype/ttf-dejavu/DejaVuSans.ttf in
/home/betawiki/software/phplot-6.1.0/phplot.php on line 1957

Change-Id: Id80bfc0f562b27d60c246a98e45d91f497d58ed1
Merge "Install dejavu fonts"