Bug 150601 Drillthrough link from pdf(frameset) should link to frameset servlet instead of run.
Description: Drillthrough link from pdf(frameset) should link to frameset servlet instead of run. Steps to reproduce: 1. New a report 2. Insert a label and define a drill through link to other report 3. Preview in Web viewer, click Print as PDF button in viewer toolbar 4. Click drill through link in pdf Expected result: Target report opens through frameset sevlet instead of run servlet. Because the pdf is displayed through frameset servlet. Actual result: Target report opened through run sevlet
viewer/org.eclipse.birt.report.viewer/birt/WEB-INF/classes/org/eclipse/birt/report/service/ReportEngineService.java
* Get engine instance.
	 * 
	 * @param servletConfig
	 * @throws BirtException
	 * 
	 */
	public synchronized static void initEngineInstance( ServletConfig servletConfig )
			throws BirtException
	{
		if ( ReportEngineService.instance != null )
		{
			return;
		}
		ReportEngineService.instance = new ReportEngineService( servletConfig );
	}
	/**
	 * Get all the files under the specified folder (including all the files
	 * under sub-folders)
	 * 
	 * @param dir -
	 *            the folder to look into
	 * @param fileList -
	 *            the fileList to be returned
	 */
	private void getAllJarFiles( File dir, ArrayList fileList )
	{
		if ( dir.exists( ) && dir.isDirectory( ) )
		{
			File[] files = dir.listFiles( );
			if ( files == null )