Bug 142939 Invalid interval will cause incorrect group action.
Description: Invalid interval will cause incorrect group action. Steps to reproduce: 1. Insert a list 2. Add a group, key is string type column, set interval to year, range to 3 3. Preview Expected result: Error msg about invald interval and ignore the invalid interval. Actual result: No error msg and only return one group with all datarows.
data/org.eclipse.birt.data/src/org/eclipse/birt/data/engine/impl/QueryExecutor.java
* 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;
	}
	/**
	 * Prepare Executor so that it is ready to execute the query
	 * 
	 * @param outerRts
	 * @param targetScope
	 * @throws DataException
	 */
	void prepareExecution( IQueryResults outerRts, Scriptable targetScope )
			throws DataException
	{
		if ( isPrepared )
			return;
		this.parentScope = targetScope;
		dataSource = findDataSource( );
		if ( outerRts != null )
		{