don't use default style as parent for OOXML cond format style, tdf#91335

Change-Id: I1388bb5ab71f6f6d174872023f085240f3bff916

sc/inc/stlsheet.hxx

@@ -22,6 +22,8 @@
 
 #include <svl/style.hxx>
 
+#include "scdllapi.h"
+
 #define SCSTYLEBIT_STANDARD     0x0001
 
 class ScStyleSheetPool;
@@ -48,6 +50,7 @@ public:
                         ScStyleSheet( const ScStyleSheet& rStyle );
 
     virtual bool        SetParent        ( const OUString& rParentName ) SAL_OVERRIDE;
+    SC_DLLPUBLIC void ResetParent();
     virtual SfxItemSet& GetItemSet       () SAL_OVERRIDE;
     virtual bool        IsUsed           () const SAL_OVERRIDE;
     virtual bool        HasFollowSupport () const SAL_OVERRIDE;

sc/source/core/data/stlsheet.cxx

@@ -121,6 +121,11 @@ bool ScStyleSheet::SetParent( const OUString& rParentName )
     return bResult;
 }
 
+void ScStyleSheet::ResetParent()
+{
+    GetItemSet().SetParent(NULL);
+}
+
 SfxItemSet& ScStyleSheet::GetItemSet()
 {
     if ( !pSet )

sc/source/filter/oox/stylesbuffer.cxx

@@ -3117,9 +3117,12 @@ OUString StylesBuffer::createDxfStyle( sal_Int32 nDxfId ) const
 
         // Create a cell style. This may overwrite an existing style if
         // one with the same name exists.
+        ScStyleSheet& rStyleSheet = ScfTools::MakeCellStyleSheet(
+                *getScDocument().GetStyleSheetPool(), rStyleName, true);
+
+        rStyleSheet.ResetParent();
         SfxItemSet& rStyleItemSet =
-            ScfTools::MakeCellStyleSheet(
-                *getScDocument().GetStyleSheetPool(), rStyleName, true).GetItemSet();
+            rStyleSheet.GetItemSet();
 
         pDxf->fillToItemSet(rStyleItemSet);
     }