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
* 
	 * @param module
	 *            the module
	 * 
	 * @return <code>true</code> if the refresh action is successful.
	 *         <code>false</code> othersize.
	 * 
	 */
	public boolean refreshStructureFromParent( Module module )
	{
		DesignElement parent = getExtendsElement( );
		if ( parent == null )
			return false;
		
		return ModelUtil.duplicateStructure( parent, this );
	}
	/**
	 * Resolve and returns the virtual parent element. If the element is not
	 * virtual element, <code>null</code> will be returned. Otherwise, find
	 * and returns the virtual parent using the <code>baseId</code>.
	 * 
	 * @return the virtual parent element.
	 */
	public DesignElement getVirtualParent( )
	{
		if ( !isVirtualElement( ) )
			return null;
		
		DesignElement parent = null;
		DesignElement cur = this;