Change AttachmentsModule.DetachSingleAttachmentToInv() to accept a SOG directly instead of an item ID to then shuffle through attachments, saving CPU busywork.

Almost all callers already had the sog to hand.
Still checking that it's really an attachment, but now by inspecting SOG.AttachedAvatar

OpenSim/Region/Framework/Interfaces/IScenePresence.cs

@@ -72,6 +72,10 @@ namespace OpenSim.Region.Framework.Interfaces
         /// <returns></returns>
         List<SceneObjectGroup> GetAttachments(uint attachmentPoint);
 
+        /// <summary>
+        /// Does this avatar have any attachments?
+        /// </summary>
+        /// <returns></returns>
         bool HasAttachments();
 
         // Don't use these methods directly.  Instead, use the AttachmentsModule