[gnome-boxes] Enable only-downscale in spice if supported

[Alexander Larsson <alexl src gnome org>]

commit af838795efb3ff6abd7f728ecb2a7c9a414174c1
Author: Alexander Larsson <alexl redhat com>
Date:   Fri Aug 31 11:01:15 2012 +0200

    Enable only-downscale in spice if supported

 src/spice-display.vala |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)
---
diff --git a/src/spice-display.vala b/src/spice-display.vala
index ff6f85d..c4f4a09 100644
--- a/src/spice-display.vala
+++ b/src/spice-display.vala
@@ -77,6 +77,8 @@ private class Boxes.SpiceDisplay: Boxes.Display, Boxes.IPropertiesProvider {
             });
             sync_config_with_display (this, display_saved_properties);
             display.scaling = true;
+            if (display.get_class ().find_property ("only-downscale") != null)
+                display.set ("only-downscale", true);
 
             displays.replace (n, display);
         }