Define only 'sata' bus explicitly

Author: Marat Bakeev

templates/vm.xml.j2

@@ -39,7 +39,7 @@
       <source pool='{{ volume.pool }}' volume='{{ volume.name }}'/>
       {% endif %}
       {% if volume.target is undefined %}
-      <target dev='vd{{ 'abcdefghijklmnopqrstuvwxyz'[loop.index - 1] }}' {% if volume.device | default(libvirt_volume_default_device) == 'cdrom' %}bus='sata'{% else %}bus='virtio'{% endif %}/>
+      <target dev='vd{{ 'abcdefghijklmnopqrstuvwxyz'[loop.index - 1] }}' {% if volume.device | default(libvirt_volume_default_device) == 'cdrom' %}bus='sata'{% endif %}/>
       {% else %}
       <target dev='{{ volume.target }}' {% if volume.device | default(libvirt_volume_default_device) == 'cdrom' %}bus='sata'{% endif %}/>
       {% endif %}