patch for #813 - when setting baselayer, we no longer redraw twice.

git-svn-id: http://svn.openlayers.org/trunk/openlayers@3706 dc9f47b5-9b13-0410-9fdd-eb0c1a62fdaf

lib/OpenLayers/Map.js

@@ -688,7 +688,7 @@ OpenLayers.Map.prototype = {
                 // changing. This is used by tiles to check if they should 
                 // draw themselves.
                 this.viewRequestID++;
-                this.baseLayer.setVisibility(true, noEvent);
+                this.baseLayer.visibility = true;
 
                 //redraw all layers
                 var center = this.getCenter();