Bug 153378 [Regression]Label text won't show up when the text key is not found
Steps to reproduce: 1.Add a label, set text to "aaa" 2.Add a resource file "a" to the report, add a text key "k1" which is not in the a.properties to the label 3.Preview in Web Viewer Expected result: Label display "aaa" when the text key is not found Actual result: Nothing in preview
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/api/util/ParameterValidationUtil.java
*            the locale information
	 * @return the formatted string
	 * 
	 */
	static private String getDisplayValue( String dataType, Object value,
			ULocale locale )
	{
		if ( DesignChoiceConstants.PARAM_TYPE_DATETIME
				.equalsIgnoreCase( dataType )
				|| value instanceof Date )
		{
			DateFormat formatter = DateFormat.getDateTimeInstance(
					DateFormat.MEDIUM, DateFormat.MEDIUM, locale );
			return formatter.format( (Date) value );
		}
		else if ( DesignChoiceConstants.PARAM_TYPE_FLOAT
				.equalsIgnoreCase( dataType )
				|| value instanceof Float || value instanceof Double )
		{
			NumberFormat formatter = NumberFormat.getNumberInstance( locale );
			return formatter.format( ( (Number) value ).doubleValue( ) );
		}
		else if ( DesignChoiceConstants.PARAM_TYPE_DECIMAL
				.equalsIgnoreCase( dataType )
				|| value instanceof BigDecimal )
		{
			NumberFormat formatter = NumberFormat.getNumberInstance( locale );
			return formatter.format( ( (BigDecimal) value ).doubleValue( ) );
		}
		else if ( DesignChoiceConstants.PARAM_TYPE_INTEGER