also remove the libxml2 include from chart2

all xml related dumper code is now in drawinglayer/source/dumper and no
longer in chart2

Change-Id: I4197774c0ef62606e8f32e47e3fbda0a0de32ae0

chart2/source/view/main/ChartView.cxx

@@ -113,10 +113,6 @@
 #include <rtl/strbuf.hxx>
 #include <rtl/oustringostreaminserter.hxx>
 
-//libxml2 for dumping
-#include <libxml/xmlwriter.h>
-
-
 //.............................................................................
 namespace chart
 {