Stop attempts to rewear already worn items from removing and reattaching.

Viewer 2/3 will sometimes attempt to rewear attachments, even though they have already been attached during the main login process.
This change ignores those attempts.
This stops script failures during login, as the rewearing was racing with the script startup code.
It might also help with attachments being abnormally put into deleted state.
Hopefully resolves some more of http://opensimulator.org/mantis/view.php?id=5644

OpenSim/Region/Framework/Scenes/SceneObjectPartInventory.cs

@@ -1035,10 +1035,15 @@ namespace OpenSim.Region.Framework.Scenes
                     item.BasePermissions = perms;
                 }
             }
+            
             m_inventorySerial++;
             HasInventoryChanged = true;
         }
 
+        /// <summary>
+        /// Returns true if this part inventory contains any scripts.  False otherwise.
+        /// </summary>
+        /// <returns></returns>
         public bool ContainsScripts()
         {
             lock (m_items)