taking the mutex before calling update is a deadlock as well

The mutex is unnecessary as update is calling join in the beginning
anyway.

Change-Id: I1dc0c415f4405b58ddbe3640fa8870bed9fefef3

chart2/source/view/charttypes/GL3DBarChart.cxx

@@ -606,7 +606,6 @@ void GL3DBarChart::render()
     if (BENCH_MARK_MODE)
         return;
 
-    osl::MutexGuard aGuard(maMutex);
     update();
 }