- fixed boot image descriptions for 32bit x86 builds (bnc #829429)
  * kernel-desktop doesn't exist for i586 anymore
  * kernel-pae doesn't exist for i586 anymore
  * don't use ix86 as arch statement because this doesn't allow
    to distinguish between i686 and i586
- don't turn arch name i686/i586 into combined ix86 name. This is
  required with regards to the previous commit handling i586 and
  i686 specific packages setup (bnc #829429)
- update unit tests due to i586/i686 vs ix86 arch name change
- fixed 32bit efi builds. the created efi binary should be
  named bootx32.efi for this architecture