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
* Context parameter name that gives the repository location of the script
	 * files to run reports.
	 */
	public static final String INIT_PARAM_SCRIPTLIB_DIR = "BIRT_VIEWER_SCRIPTLIB_DIR"; 
	/**
	 * Context parameter name that determines the search strategy of searching
	 * report resources. True if only search the working folder, otherwise
	 * false.
	 */
	public static final String INIT_PARAM_WORKING_FOLDER_ACCESS_ONLY = "WORKING_FOLDER_ACCESS_ONLY"; 
	/**
	 * The parameter name that gives the repository location to put the created
	 * documents and report design files.
	 */
	public static final String INIT_PARAM_DOCUMENT_FOLDER = "BIRT_VIEWER_DOCUMENT_FOLDER"; 
	/**
	 * Context parameter name that gives the absolute resource location
	 * directory.
	 */
	public static final String INIT_PARAM_BIRT_RESOURCE_PATH = "BIRT_RESOURCE_PATH"; 
	/**
	 * Context parameter name that gives preview report max rows limited.
	 */
	public static final String INIT_PARAM_VIEWER_MAXROWS = "BIRT_VIEWER_MAX_ROWS"; 
	/**
	 * Context parameter name that gives preview report cube fetch levels
	 * limited.
	 */
	public static final String INIT_PARAM_VIEWER_MAXCUBELEVELS = "BIRT_VIEWER_MAX_CUBE_LEVELS"; 
	/**