mantis 3315: change the control of script flag running (needs testing)

OpenSim/Region/ScriptEngine/YEngine/XMRScriptUThread.cs

@@ -25,6 +25,7 @@
  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
+using OpenSim.Framework;
 using System;
 using System.Collections.Generic;
 using System.Reflection;