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 new query string with new parameter value
	 */
	public static String getEncodedQueryString( HttpServletRequest request,
			String name, String value )
	{
		String queryString = ""; 
		Enumeration e = request.getParameterNames( );
		Set nullParams = getParameterValues( request, PARAM_ISNULL );
		boolean isFirst = true;
		while ( e.hasMoreElements( ) )
		{
			String paramName = (String) e.nextElement( );
			if ( paramName != null
					&& !paramName.equalsIgnoreCase( PARAM_ISNULL ) )
			{
				String paramValue = getParameter( request, paramName, false );
				if ( nullParams != null
						&& nullParams.remove( toUTFString( paramName ) )
						&& !paramName.equalsIgnoreCase( name ) ) 
				
				
				{
					paramName = urlEncode( paramName, ISO_8859_1_ENCODE );
					queryString += ( isFirst ? "" : PARAMETER_SEPARATOR ) + PARAM_ISNULL + EQUALS_OPERATOR + paramName; 
					isFirst = false;
					continue;
				}
				if ( paramName.equalsIgnoreCase( name ) )
				{
					paramValue = value;