Bug 161222 Decoration label should be optional in Gantt Chart
It should not be mandatory to specify a decoration label for Gantt Charts, this can be left blank. Currently the UI and Engine enforce a data definition to be specified for it.
chart/org.eclipse.birt.chart.engine/src/org/eclipse/birt/chart/internal/datafeed/ResultSetDataSet.java
* @see org.eclipse.birt.chart.datafeed.IResultSetDataSet#next()
	 */
	public Object[] next( )
	{
		lRow++;
		if ( lRow > lEndRow )
		{
			return null;
		}
		if ( listMode )
		{
			oaTuple[0] = it.next( );
		}
		else
		{
			final Object[] oaResultSet = (Object[]) it.next( );
			for ( int i = 0; i < iColumnCount; i++ )
			{
				oaTuple[i] = oaResultSet[iaColumnIndexes[i]];
			}
		}
		return oaTuple;
	}
	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.birt.chart.datafeed.IResultSetDataSet#getDataType()
	 */
	public int getDataType( )
	{