Bug 149783 Display text for extend elelment in master page is not found
Steps to reproduce: 1.New a library, add a properties file for the library, add pair"k1=actuate" to the properties file 2.Add a label "aaa" in master page header, set "k1" as the text key 3.Publish the library 4.New a report, extend lib.masterpage 5.Open extended master page in report Expected result: label shows display text "actuate" Actual result: label shows text "aaa"
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/util/ModelUtil.java
*            Name of property
	 * @param locale
	 *            the locale
	 * @return externalized value.
	 */
	public static String getExternalizedValue( DesignElement element,
			String propIDName, String propName, ULocale locale )
	{
		if ( element == null )
			return null;
		String textKey = searchForExternalizedValue( element, propIDName,
				locale );
		if ( !StringUtil.isBlank( textKey ) )
			return textKey;
		
		return element.getStringProperty( element.getRoot( ), propName );
	}
	/**
	 * Checks if report design contains the same library as the target library
	 * which user wants to export. If no exception throws , that stands for user
	 * can export report design to library. Comparing with the obsolute file
	 * name path, if file is the same , throw <code>SemanticException</code>
	 * which error code is include recursive error.
	 * 
	 * For example , the path of library is "C:\test\lib.xml" .The followings
	 * will throw semantic exception:
	 * 
	 * <ul>
	 * <li> design file and library in the same folder: </li>
	 * <li> <list-property name="libraries"> <structure> <property