Comment # 2 on bug 947842 from Dominique Leuenberger

(In reply to Takashi Iwai from comment #0)

> The likely reason is that the package doesn't update the gtk icon theme.  It
> should have %icon_theme_cache_post and %icon_theme_cache_postun in post and
> postun triggers.

This is easy to confirm: do the icons show up properly after a system reboot?