dont use SwClient/SwModify in unocore: ChartDataProvider

- and to the couragous person writing that comment:
  * yes, likely you should have come back to check if this was
    superfluous
  * no, you didnt (so far)

Change-Id: I56633aee4b49979b60417f88235e9393c0bc48c8
Reviewed-on: https://gerrit.libreoffice.org/54895Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Björn Michaelsen <bjoern.michaelsen@libreoffice.org>

sw/inc/unochart.hxx

@@ -100,8 +100,7 @@ typedef cppu::WeakImplHelper
 SwChartDataProviderBaseClass;
 
 class SwChartDataProvider :
-    public SwChartDataProviderBaseClass,
-    public SwClient
+    public SwChartDataProviderBaseClass
 {
 
     // used to keep weak-references to all data-sequences of a single table
@@ -142,10 +141,6 @@ class SwChartDataProvider :
 
     static OUString GetBrokenCellRangeForExport( const OUString &rCellRangeRepresentation );
 
-protected:
-    //SwClient
-    virtual void Modify( const SfxPoolItem* pOld, const SfxPoolItem *pNew) override;
-
 public:
     SwChartDataProvider( const SwDoc* pDoc );
     virtual ~SwChartDataProvider() override;

sw/source/core/unocore/unochart.cxx

@@ -1455,12 +1455,6 @@ uno::Sequence< OUString > SAL_CALL SwChartDataProvider::getSupportedServiceNames
     return { "com.sun.star.chart2.data.DataProvider"};
 }
 
-void SwChartDataProvider::Modify( const SfxPoolItem* pOld, const SfxPoolItem *pNew)
-{
-    // actually this function should be superfluous (need to check later)
-    ClientModify(this, pOld, pNew );
-}
-
 void SwChartDataProvider::AddDataSequence( const SwTable &rTable, uno::Reference< chart2::data::XDataSequence > const &rxDataSequence )
 {
     aDataSequences[ &rTable ].insert( rxDataSequence );