Display error message if a customer tries to open the customer portal with an unsupported browser

At the moment when a customer is using e.g. Internet Explorer 8 the service desk portal page shows absolutly nothing.

/servicedesk/customer/portals

You see only a white screen. I think the root cause is the Analytics plugin. This will break the whole page.

The normal JIRA login page displays a message that the browser is not supported.

This is something that the customer understands. A white page looks like a server side problem.