fix voor xml syntax fout in web.xml

`org.xml.sax.SAXParseException; systemId:
jndi:/localhost/cbsviewer/WEB-INF/web.xml; lineNumber: 77; columnNumber:
7; The string "--" is not permitted within comments.`

geintroduceerd in 95ab499f7e9f20f655bded7c35d95092f125fccc