Bug 143173 No error for recursive including when exporting a report to a library
Steps to reproduce: 1.New a library named "Lib", add a lable in it 2.New a report, extends Lib.label 3.Export the report, choose target library "Lib" Expected result: Error to warn the recursive including Actual result: The target library includes itself without error
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/util/ModelUtil.java
return copy;
		}
		catch ( CloneNotSupportedException e )
		{
			assert false;
			return null;
		}
	}
	/**
	 * Returns externalized message. If There is no externalized message, return
	 * null.
	 * 
	 * @param element
	 *            Design element.
	 * @param propName
	 *            Name of property
	 * @return externalized message.
	 */
	private static String searchForExternalizedValue( DesignElement element,
			String propIDName )
	{
		while ( element != null )
		{
			Module root = element.getRoot( );
			String textKey = (String) element.getLocalProperty( root,
					propIDName );
			if ( !StringUtil.isBlank( textKey ) )
			{
				String externalizedText = root.getMessage( textKey );
				return externalizedText;