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
* extracting appropriate columns and a row range from a resultset
	 * 
	 * @param liResultSet
	 * @param iColumnIndex
	 * @param lStartRow
	 * @param lEndRow
	 */
	public ResultSetDataSet( ResultSetWrapper rsw, int[] iaColumnIndexes,
			long lStartRow, long lEndRow )
	{
		this.rsw = rsw;
		this.iColumnCount = iaColumnIndexes.length;
		this.iaColumnIndexes = iaColumnIndexes;
		this.lStartRow = lStartRow;
		this.lEndRow = lEndRow;
		this.oaTuple = new Object[iaColumnIndexes.length];
		this.listMode = false;
		this.listDataType = IConstants.UNDEFINED;
		
		it = rsw.iterator( );
		if ( lRow < lStartRow )
		{
			while ( lRow < lStartRow )
			{
				lRow++;
				it.next( );
			}
		}
	}
	/**