v2v: glance: Set hw_video_model property to qxl|cirrus (RHBZ#1374651).

Thanks: Vladik Romanovsky, Ming Xie.

v2v/output_glance.ml

@@ -92,6 +92,10 @@ object
            | Virtio_net -> "virtio"
            | E1000 -> "e1000"
            | RTL8139 -> "rtl8139");
+          "hw_video_model",
+          (match guestcaps.gcaps_video with
+           | QXL -> "qxl"
+           | Cirrus -> "cirrus");
           "architecture", guestcaps.gcaps_arch;
           "hypervisor_type", "kvm";
           "vm_mode", "hvm";