Bug 124620 Referenced Parameter icon should be invalid if the parameter in library is deleted
Description: Referenced parameter icon should be invalid if the source parameter in library is deleted. Steps to reproduce: 1.Create a library. Insert a report scalar parameter. 2.Create a report, use the above library. In the library explorer, pull the parameter to the data explorer view of report. 3.Open the library file, delete the parameter. Then reopen the report design file, the icon of parameter seems nothing happened. But if those operations happened in dataset, the icon of dataset in the report will be invalid. It is acceptable. Expected Result: The icon of referenced parameter should be invalid.
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/core/DesignElement.java
ElementPropertyDefn prop = (ElementPropertyDefn) getDefn( )
				.getProperty( propName );
		if ( prop == null )
			prop = getUserPropertyDefn( propName );
		return prop;
	}
	/**
	 * Validates that the given property name is either a system-defined or
	 * user-defined property.
	 * <p>
	 * Part of: Property system.
	 * 
	 * @param propName
	 *            The name of the property to validate.
	 * @throws PropertyNameException
	 *             If the property is undefined.
	 */
	void validatePropertyName( String propName ) throws PropertyNameException
	{
		if ( getPropertyDefn( propName ) == null )
			throw new PropertyNameException( this, propName );
	}
	/**
	 * Validates the given property value. Validation may map the value onto a
	 * new value that should be used for the actual property update.
	 * <p>
	 * Part of: Property system.
	 * 
	 * @param module
	 *            the module