virt-xml-validate needs xmllint

from libxml2-utils.

Closes: #584869

debian/control

@@ -24,7 +24,8 @@ Architecture: any
 Depends: ${shlibs:Depends}, ${misc:Depends}, adduser, libvirt0 (= ${binary:Version}), logrotate
 Enhances: qemu, qemu-kvm, xen
 Section: admin
-Recommends: netcat-openbsd, bridge-utils, dnsmasq-base (>= 2.46-1), iptables, qemu-kvm | qemu (>= 0.9.1)
+Recommends: netcat-openbsd, bridge-utils, dnsmasq-base (>= 2.46-1), iptables, qemu-kvm | qemu (>= 0.9.1),
+ libxml2-utils
 Suggests: policykit-1
 Description: the programs for the libvirt library
  Libvirt is a C toolkit to interact with the virtualization capabilities