Bug 197589 Need constant for automaic attribute name "DateTime"
Currently when set dateTimeLevelType for cube level, model will automatically create a built-in attribute "DateTime". But the name is hard-coded. We need a public constant for this name to allow UI to access it.
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/command/PropertyCommand.java
throw new SemanticError( element,
						SemanticError.DESIGN_EXCEPTION_CANNOT_SPECIFY_PAGE_SIZE );
			}
		}
		value = validateValue( prop, value );
		if ( value instanceof ElementRefValue
				&& prop.getTypeCode( ) == IPropertyType.ELEMENT_REF_TYPE )
		{
			checkRecursiveElementReference( prop, (ElementRefValue) value );
		}
		if ( element instanceof GroupElement
				&& IGroupElementModel.GROUP_NAME_PROP.equals( prop.getName( ) ) )
		{
			if ( !isGroupNameValidInContext( (String) value ) )
				throw new NameException( element, (String) value,
						NameException.DESIGN_EXCEPTION_DUPLICATE );
		}
		
		if ( prop.isIntrinsic( ) )
		{
			setIntrinsicProperty( prop, value );
			return;
		}
		if ( IDesignElementModel.REF_TEMPLATE_PARAMETER_PROP.equals( prop
				.getName( ) )
				&& value == null )
		{
			clearRefTemplateParameterProp( prop, value );
			return;
		}