Fix openSUSE cloud image download and extraction
Fix openSUSE cloud image download and extraction

Use the latest available version of the rootfs (instead of a qcow2
image) to simplify rootfs extraction.

Change-Id: Ic3a646b923738464b5217d799758b6980b2deaf2

rdo-management/diskimage-builder,switch-ch/diskimage-builder,JioCloud/diskimage-builder,takahashinobuyuki/diskimage-builder,eantyshev/diskimage-builder,JioCloud/diskimage-builder,eantyshev/diskimage-builder,zioproto/diskimage-builder,openstack/diskimage-builder,zioproto/diskimage-builder,varunarya10/diskimage-builder,switch-ch/diskimage-builder,NaohiroTamura/diskimage-builder,varunarya10/diskimage-builder,rdo-management/diskimage-builder,openstack/diskimage-builder,CSC-IT-Center-for-Science/diskimage-builder,NaohiroTamura/diskimage-builder,takahashinobuyuki/diskimage-builder,CSC-IT-Center-for-Science/diskimage-builder