Fixed notification enable logic and test when On Upgrade is disabled.

src/NzbDrone.Core/Notifications/NotificationDefinition.cs

@@ -20,7 +20,7 @@ public override Boolean Enable
         {
             get
             {
-                return OnGrab || (OnDownload && OnUpgrade);
+                return OnGrab || OnDownload || (OnDownload && OnUpgrade);
             }
         }
     }