It seems that nearestExistingFont() gets the same result of
`fc-match font-name`, which is basically the sans serif default font
on the system; this seems redundant as KFontChooser will fallback to
selecting the first font family in the list if the initial font it
was called with doesn't exist _and_ KFontChooser always puts "Sans Serif",
"Serif" and "Monospace" at the top of the list.
Removing nearestExistingFont() solves the issue in bug 420287 as
the font it returns will have the styleName property set, after we
went to so much trouble to clear that property so that setBold() can
work.
CCBUG: 420287