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
* built-in property name, or a user-defined property name. The value is set
	 * without checking the name for validity.
	 * <p>
	 * Part of: Property value system.
	 * 
	 * @param module
	 *            the module
	 * @param propName
	 *            name of the property to set. Must be valid. Can be a
	 *            system-defined or user-defined property name.
	 * @return the property value, or null if no value is set
	 */
	public Object getLocalProperty( Module module, String propName )
	{
		ElementPropertyDefn prop = getPropertyDefn( propName );
		if ( prop == null )
			return null;
		return getLocalProperty( module, prop );
	}
	/**
	 * Gets a property value given its definition. This version checks only this
	 * one object. That is, it gets the "local" property value. The property
	 * name must also be valid for this object.
	 * <p>
	 * Part of: Property value system.
	 * 
	 * @param module
	 *            the module
	 * @param prop
	 *            The property definition.