Add support for arm64 images

This patch enables proper support for arm64 images by disabling VNC support
and adding several properties to the image in glance that are necessary to
boot correctly:
  hw_cdrom_bus=virtio
  hw_machine_type=virt
  os_command_line='console=ttyAMA0'

Change-Id: I68c9a5e0e083af2f92875c3bdf70df750f6e4d8f
diff --git a/functions b/functions
index 4dc20e7..2078db1 100644
--- a/functions
+++ b/functions
@@ -287,6 +287,10 @@
         img_property="--property hw_cdrom_bus=scsi"
     fi
 
+    if is_arch "aarch64"; then
+        img_property="--property hw_machine_type=virt --property hw_cdrom_bus=virtio --property os_command_line='console=ttyAMA0'"
+    fi
+
     if [ "$container_format" = "bare" ]; then
         if [ "$unpack" = "zcat" ]; then
             openstack --os-token $token --os-url $GLANCE_SERVICE_PROTOCOL://$GLANCE_HOSTPORT image create "$image_name" $img_property --public --container-format=$container_format --disk-format $disk_format < <(zcat --force "${image}")