Bug 200812 Issue when remove one separator setting in viewer.property[0002]
Description: Issue when remove one separator setting in viewer.property Build number:2.2.1.v200708220927 Steps to reproduce: 1. Deploy birt. 2. Open viewer.properties under WEB-INF folder. 3. Delete "viewer.sep.0=," line 4. Start server. 5. Preview report. 6. Export Data, select columns and select "Comma(,)", click OK. Expected result: Comma(,) isn't in the separator list. Actual result: Nothing happened after step6 and no error logs. Error log:n/a
viewer/org.eclipse.birt.report.viewer/birt/WEB-INF/classes/org/eclipse/birt/report/utility/ParameterAccessor.java
* @return
	 */
	public static char getSep( HttpServletRequest request )
	{
		String sepKey = getParameter( request, PARAM_SEP );
		if ( sepKey == null )
			return DEFAULT_SEP;
		String key = "viewer.sep." + sepKey; 
		String sep = getInitProp( key );
		if ( sep.length( ) <= 0 )
			return DEFAULT_SEP;
		return sep.charAt( 0 );
	}
	/**
	 * Returns whether exports column's data type
	 * 
	 * @param request
	 * @return
	 */
	public static boolean isExportDataType( HttpServletRequest request )
	{
		String flag = getParameter( request, PARAM_EXPORT_DATATYPE );
		if ( "true".equalsIgnoreCase( flag ) ) 
			return true;
		return false;
	}
	/**
	 * Set isCleanSessionFiles
	 * 
	 * @param request