Bug 212712 run --config "logdir=xxx" in genReport can not create folder auto[00]
Descriiption: run --config "logdir=xxx" in genReport can not create folder auto[00] Run the genReport, and add the variable of --config "logdir=xxx". If xxx is not exist, it will pop up the error. Expected: It can create the folder auto.
engine/org.eclipse.birt.report.engine/src/org/eclipse/birt/report/engine/api/impl/EngineLogger.java
rootLogger.setLevel( newLevel );
		}
	}
	/**
	 * This is a utility function that will create an unique file name with the
	 * timestamp information in the file name and append the file name into the
	 * directory name. For example, if the directory name is C:\Log, the
	 * returned file name will be C:\Log\ReportEngine_2005_02_26_11_26_56.log.
	 * 
	 * @param directoryName -
	 *            the directory name of the log file.
	 * @return An unique Log file name which is the directory name plus the file
	 *         name.
	 */
	private static String generateUniqueLogFileName( String directoryName )
	{
		SimpleDateFormat df = new SimpleDateFormat( "yyyy_MM_dd_HH_mm_ss" ); 
		String dateTimeString = df.format( new Date( ) );
		if ( directoryName == null )
			directoryName = ""; 
		else if ( directoryName.length( ) > 0 )
			directoryName += System.getProperty( "file.separator" ); 
		return new String( directoryName
				+ "ReportEngine_" + dateTimeString + ".log" ); 
	}
	private static Logger createFileLogger( String dirName )
	{
		try
		{
			Handler logFileHandler = new FileHandler(