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
*/
	public static final String PARAM_ISREPORTLET = "__isreportlet";
	/**
	 * URL parameter name to indicate the export encoding.
	 */
	public static final String PARAM_EXPORT_ENCODING = "__exportEncoding";
	/**
	 * URL parameter name to indicate the CSV separator.
	 */
	public static final String PARAM_SEP = "__sep";
	/**
	 * URL parameter name to indicate whether exports column's data type.
	 */
	public static final String PARAM_EXPORT_DATATYPE = "__exportdatatype";
	/**
	 * URL parameter name to indicate if fit to page when render report as PDF.
	 */
	public static final String PARAM_FIT_TO_PAGE = "__fittopage";
	/**
	 * URL parameter name to indicate if pagebreak pagination only when render
	 * report as PDF.
	 */
	public static final String PARAM_PAGEBREAK_ONLY = "__pagebreakonly";
	/**
	 * Indentify the display text of select parameter
	 */
	public static final String PREFIX_DISPLAY_TEXT = "__isdisplay__"; 
	/**
	 * Indentify the parameter value is a locale string
	 */