Write /dev/vd* instead of vd* in mounts.cfg
Write /dev/vd* instead of vd* in mounts.cfg

Fixes a regression introduced by d74b4350: the init-qemu tool expects
/dev/vd* sources to create the block device, while we were just having
vd*. Write again /dev/vd* to mounts.cfg.

libvirt/libvirt-sandbox,agx/libvirt-sandbox-debian,agx/libvirt-sandbox-debian,erenyagdiran/libvirt-sandbox,erenyagdiran/libvirt-sandbox,libvirt/libvirt-sandbox,agx/libvirt-sandbox-debian,agx/libvirt-sandbox-debian,libvirt/libvirt-sandbox,erenyagdiran/libvirt-sandbox,erenyagdiran/libvirt-sandbox,agx/libvirt-sandbox-debian