fixed out of bounds vector access

in ScColumn::FindNextVisibleRowWithContent() if starting from the
position all including the last present cell of a column are blank

Change-Id: I0270331444f1707b6ad413f6127ae4c2cf0b1984

sc/source/core/data/column2.cxx

@@ -1353,7 +1353,7 @@ SCROW ScColumn::FindNextVisibleRowWithContent(SCROW nRow, bool bForward) const
             bool bThere = Search( nRow, nIndex );
             if( bThere && !maItems[nIndex].pCell->IsBlank())
                 return nRow;
-            else if(nIndex >= maItems.size())
+            else if((bThere ? nIndex+1 : nIndex) >= maItems.size())
                 return MAXROW;
             else
             {