Make the Eluna mutex static.

It was previously unsafe to reload Eluna because it had to be reloaded
with the mutex unlocked. This is because the mutex's lifespan was shorter
than the Eluna instance it was guarding.

HookMgr.cpp

@@ -463,13 +463,13 @@ void Eluna::OnShutdownCancel()
 
 void Eluna::OnWorldUpdate(uint32 diff)
 {
+    ELUNA_LOCK(this);
     if (reload)
     {
         ReloadEluna();
         return;
     }
 
-    ELUNA_LOCK(this);
     eventMgr->globalProcessor->Update(diff);
 
     Push(diff);