po/make-images: Drop unnecessary fontmap
po/make-images: Drop unnecessary fontmap

This was causing problems building on Jessie, and turns out to be unused
anyway:
   AttributeError: 'gi.repository.PangoCairo' object has no attribute 'font_map_get_default'

Signed-off-by: Philip Withnall <29c2a2ac2a854b9cf047275aa9de346d096be2e0@endlessm.com>

fwupd/fwupd,fwupd/fwupd,superm1/fwupd,hughsie/fwupd,hughsie/fwupd,hughsie/fwupd,vathpela/fwupd,fwupd/fwupd,superm1/fwupd,fwupd/fwupd,superm1/fwupd,vathpela/fwupd,hughsie/fwupd,vathpela/fwupd,vathpela/fwupd