Lua: Fix lua_state::do_once()

include/library/luabase.hpp

@@ -293,7 +293,7 @@ public:
  * Do something just once per VM.
  *
  * Parameter key: The do-once key value.
- * Returns: 
+ * Returns: True if called the first time for given key on given VM, false otherwise.
  */
 	bool do_once(void* key);
 

src/library/luabase.cpp

@@ -174,6 +174,6 @@ bool lua_state::do_once(void* key)
 		return true;
 	} else {
 		pop(1);
-		return true;
+		return false;
 	}
 }