Bug 132805 Set descending to outer group will affect inner group.
Description: Set descending to outer group will affect inner group. Steps to reproduce: 1. New a sample datasource and dataset from orders. 2. Drag the dataset to Layout. 3. Add a group on ordernumber, interval 10, descending. 4. Add another group on orderdate, interval day 2, ascending. 5. Preview. Expected result: Data are grouped correctly. Actual result: Inner group didn't work unless you set outer group's sort to asc.
data/org.eclipse.birt.data/src/org/eclipse/birt/data/engine/impl/QueryExecutor.java
* 
	 * @return
	 */
	abstract protected IQuery createOdiQuery( ) throws DataException;
	
	/**
	 * Prepares the ODI query
	 */
	protected void prepareOdiQuery( ) throws DataException
	{
	}
	
	/**
	 * Executes the ODI query to reproduce a ODI result set
	 * @param eventHandler 
	 * 
	 * @return
	 */
	abstract protected IResultIterator executeOdiQuery(
			IEventHandler eventHandler ) throws DataException;
		
	/**
	 * @param context
	 */
	void setAppContext( Map context )
	{
	    queryAppContext = context;
	}
	
	/**