trails : fix compilation error

hrt/prefab/l3d/Trails.hx

@@ -470,7 +470,7 @@ class TrailObj extends h3d.scene.Mesh {
 
 		updateParams();
 
-		if (trails != null && trails.length > 0) {
+		if (trails != null) {
 			var pos = this.getAbsPos();
 			addPoint(trails[0], pos.tx, pos.ty, pos.tz, ECamera, 1.0);
 		}