Bug 189100 [Regression]X-axis data column issue[0001]
Description: [Regression]X-axis data column issue[0001] Step: 1.New a sample datasource and dataset from OFFICES 2.New a chart and use the dataset 3.Change the data type of OFFICECODE from string to integer. 4.Drop the column of OFFICECODE to Value(Y)Series. Actual result: Show the error message: Unable to use a text data to render a numerical/datetime axis.
data/org.eclipse.birt.data/src/org/eclipse/birt/data/engine/impl/BindingColumnsEvalUtil.java
if ( exprValueMap.get( bindingColumn.columnName ) == null )
				exprValueMap.put( bindingColumn.columnName, exprValue );
		}
		saveHelper.doSaveExpr( exprValueMap );
		return exprValueMap;
	}
	/**
	 * @param baseExpr
	 * @param exprType
	 * @param valueMap
	 * @throws DataException
	 */
	private Object evaluateValue( BindingColumn bindingColumn, int exprType )
			throws DataException
	{
		Object exprValue = null;
		try
		{
			boolean getValue = false;
			if ( isBasedOnRD == true )
			{
				String columnName = bindingColumn.columnName;
				if ( evalHelper.contains( columnName ) )
				{
					getValue = true;
					exprValue = evalHelper.getValue( columnName );
				}
			}
			
			if ( getValue == false )