Fix for bug 41433 (assert/crash in DNS for offline-online) We were not destroying the monitor in shutdown. r=bryner

netwerk/dns/src/nsDnsService.cpp

@@ -1236,6 +1236,12 @@ nsDNSService::Shutdown()
     // Have to break the cycle here, otherwise nsDNSService holds onto the thread
     // and the thread holds onto the nsDNSService via its mRunnable
     mThread = nsnull;
+
+	if (mMonitor) 
+	{
+        nsAutoMonitor::DestroyMonitor(mMonitor);
+		mMonitor = nsnull;
+    }
     
     return rv;
 }