copied color scale formulas also need to listen to the new document

Change-Id: I2d642ba40454822e67a9c2c70f99d15459826f3b

sc/source/core/data/colorscale.cxx

@@ -63,6 +63,7 @@ ScColorScaleEntry::ScColorScaleEntry(ScDocument* pDoc, const ScColorScaleEntry&
     if(rEntry.mpCell)
     {
         mpCell.reset(static_cast<ScFormulaCell*>(rEntry.mpCell->Clone(*pDoc, SC_CLONECELL_NOMAKEABS_EXTERNAL)));
+        mpCell->StartListeningTo( pDoc );
     }
 }