Bug 121498 When datasource/dataset deleted, the datasource/dataset property binding element haven't been deleted
When deleted the datasource/dataset, the datasource/dataset property binding element haven't been deleted. Expected result: This operation must be a transaction.
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/command/ContentCommand.java
*/
	private void adjustReferenceClients( ReferenceableElement referred,
			boolean unresolveReference ) throws SemanticException
	{
		List clients = new ArrayList( referred.getClientList( ) );
		Iterator iter = clients.iterator( );
		while ( iter.hasNext( ) )
		{
			BackRef ref = (BackRef) iter.next( );
			DesignElement client = ref.element;
			if ( unresolveReference )
			{
				BackRefRecord record = new ElementBackRefRecord( module,
						referred, client, ref.propName );
				getActivityStack( ).execute( record );
			}
			else
			{
				if ( referred.isStyle( ) )
				{
					StyleCommand clientCmd = new StyleCommand( module, client );
					clientCmd.setStyleElement( null );
				}
				else
				{
					PropertyCommand cmd = new PropertyCommand( module, client );
					cmd.setProperty( ref.propName, null );
				}
			}
		}