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/api/DesignElementHandle.java
* 
	 * @param propName
	 *            the property name
	 * @param value
	 *            the value to set
	 * @throws SemanticException
	 *             if the property is undefined on the element or the value is
	 *             invalid.
	 */
	public void setProperty( String propName, Object value )
			throws SemanticException
	{
		
		DesignElement element = getElement( );
		PropertyCommand cmd = new PropertyCommand( module, element );
		cmd.setProperty( propName, value );
	}
	/**
	 * Sets the value of a property to an integer.
	 * 
	 * @param propName
	 *            the property name
	 * @param value
	 *            the value to set
	 * @throws SemanticException
	 *             If the property value cannot be converted from an integer, or
	 *             if the value of a choice is incorrect.
	 */
	public void setIntProperty( String propName, int value )
			throws SemanticException