deleted unneeded if

getStringArrayValue never returns null

tools/cooja/java/org/contikios/cooja/plugins/Visualizer.java

@@ -212,14 +212,13 @@ public class Visualizer extends VisPlugin implements HasQuickHelp {
 
     /* Register external visualizers */
     String[] skins = gui.getProjectConfig().getStringArrayValue(Visualizer.class, "SKINS");
-    if (skins != null) {
+    
     for (String skinClass: skins) {
       Class<? extends VisualizerSkin> skin = gui.tryLoadClass(this, VisualizerSkin.class, skinClass);
       if (registerVisualizerSkin(skin)) {
         logger.info("Registered external visualizer: " + skinClass);
       }
     }
-    }
 
 
     /* Menus */