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
* @return The property value, or null if no value is set.
	 */
	public Object getLocalProperty( Module module, ElementPropertyDefn prop )
	{
		if ( prop.isIntrinsic( ) )
		{
			
			return getIntrinsicProperty( prop.getName( ) );
		}
		
		if ( prop.getTypeCode( ) == PropertyType.ELEMENT_REF_TYPE )
		{
			return resolveElementReference( module, prop );
		}
		
		if ( prop.getTypeCode( ) == PropertyType.STRUCT_REF_TYPE )
		{
			return resolveStructReference( module, prop );
		}
		
		return propValues.get( prop.getName( ) );
	}
	/**
	 * Returns the value of an intrinsic property. Derived classes should
	 * override this to handle their own intrinsics. Clients should call the
	 * getProperty( ) or getLocalProperty( ) methods instead of calling this
	 * method directly.
	 * 
	 * @param propName
	 *            name of the intrinsic