libxkutil: clean entire device structure to avoid memory corruption
libxkutil: clean entire device structure to avoid memory corruption

If cleanup_virt_device is called twice (e.g. during modify resource)
a double free can occur because only the dev substructure has
been memset to zero. Now zeroing the entire structure.

Signed-off-by: Viktor Mihajlovski <a96a137ca8976b5ff3114c85be7aeb3b6464dad7@linux.vnet.ibm.com>

libvirt/libvirt-cim,libvirt/libvirt-cim,libvirt/libvirt-cim