Fix hsv==null

git-svn-id: https://redmine.imt-atlantique.fr/svn/xaal/code/Python/branches/0.7@2951 b32b6428-25c9-4566-ad07-03861ab6144f

apps/dashboard/xaal/dashboard/static/tags/lamp_color.tag

@@ -72,7 +72,7 @@
     this.brightness = data['attributes']['brightness']
 
 
-    if (mode == 'color') {
+    if ((mode == 'color') && (hsv!=null)) {
       rgb=hsv2rgb(hsv[0], hsv[1], hsv[2])
       r = Math.round(rgb[0] * 255)
       g = Math.round(rgb[1] * 255)