Removed third level menu of derivate

uitwww/navbar.json

@@ -12,7 +12,8 @@
     {
         "name": "Scopri Ubuntu",
         "endpoint": "pages.scopri-ubuntu_index",
-        "subs": [
+        "subs": []
+    },
     {
 	"name": "Derivate",
 	"endpoint": "pages.derivate_index",
@@ -50,8 +51,6 @@
 		    "endpoint": "pages.derivate_mythbuntu_index"
 		}
 	]
-	    }
-	]
      },
      {
         "name": "Supporto",