Bug 155958 Backward compatibility on 'resultset' property
Before 2.0 build, we always take the 'resultset' property on as resultset hint function. But currently, it is different.'resultset' property is to keep the oda resultset metadata,'resultsetHints' replace the function of 'resultset' as the real hints property. Currently Model has done backward compatibility on transform between 'resultset' and 'resultsetHints' by copying 'resultset' to 'resultsetHints', but 'resultset''s value still exist, it will break the current impl when fetching this property, because now we have taken this property to save the metadata of Oda resultset not hints info. To make old report design working fine, we should clear 'resultset' property, then we can use it as real resultset property.
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/parser/OdaDataSetState.java
* Returns the result set column in the given position.
	 * 
	 * @param pos
	 *            the position
	 * @return the matched result set column
	 */
	private static OdaResultSetColumn findResultSet( List resultSets,
			String columnName, Integer pos )
	{
		for ( int i = 0; i < resultSets.size( ); i++ )
		{
			OdaResultSetColumn setColumn = (OdaResultSetColumn) resultSets
					.get( i );
			
			if ( ( pos != null && pos.equals( setColumn.getPosition( ) ) )
					|| ( columnName != null && columnName.equals( setColumn
							.getColumnName( ) ) ) )
				return setColumn;
		}
		return null;
	}
	/**
	 * Returns a OdaResultSetColumn that maps from ResultSetColumn.
	 * 
	 * @param oldColumn
	 *            the result set column to convert
	 * @return the new OdaResultSetColumn
	 */
	private static OdaResultSetColumn convertResultSetColumnToOdaResultSetColumn(
			ResultSetColumn oldColumn )