Bug 122854 There is redundant columns in "available columns" list in "export data" dialog.
Description: There is redundant columns in "available columns" list in "export data" dialog. Steps to reproduce: 1. Preview attached design in web viewer. 2. Select the table and click on "export" button. 3. There is a "detail" column name in "available columns" list which is not data set column.
engine/org.eclipse.birt.report.engine/src/org/eclipse/birt/report/engine/ir/Report.java
* 
	 * @see org.eclipse.birt.report.engine.analysis.IReportQuery
	 * @return the list of the query
	 */
	public ArrayList getQueries( )
	{
		return this.queries;
	}
	public HashMap getQueryIDs( )
	{
		return this.queryIDs;
	}
	/**
	 * Puts all the report parameters including those appear inside parameter
	 * groups to the <code>allParameters</code> object.
	 * 
	 * @param params
	 *            A collection of parameters and parameter groups.
	 */
	protected void flattenParameter( ArrayList params )
	{
		assert allParameters != null;
		assert params != null;
		IParameterDefnBase param;
		for ( int n = 0; n < params.size( ); n++ )
		{
			param = (IParameterDefnBase) params.get( n );
			if ( param.getParameterType( ) == IParameterDefnBase.PARAMETER_GROUP )
			{
				flattenParameter( ( (IParameterGroupDefn) param ).getContents( ) );