- fix product media creation for non-x86_64 when EFI
  boot support is enabled (bnc #804428)
- make sure GRUB_TERMINAL is set in etc/default grub to make
  yast bootloader happy. if yast can't find this setting it
  switches to 'console' which deactivates the graphical grub2
  console (bnc #804725)
- fix iso creation for non-EFI medias again