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
DesignElement element = this;
		if ( element instanceof TemplateParameterDefinition )
		{
			List clients = ( (TemplateParameterDefinition) element )
					.getClientList( );
			if ( clients.size( ) != 0 )
				return false;
		}
		return true;
	}
	/**
	 * Determines if the slot can contain a given element.
	 * 
	 * @param module
	 *            the module
	 * @param slotId
	 *            the slot id
	 * @param element
	 *            the element to insert
	 * @return <code>true</code> if the current element can contain the
	 *         <code>element</code>, otherwise <code>false</code>.
	 */
	public final boolean canContain( Module module, int slotId,
			DesignElement element )
	{
		boolean retValue = canContainInRom( slotId, element.getDefn( ) );
		if ( !retValue )
			return false;