Due to problems in the Idiap main server:

https://secure.idiap.ch/bugzilla5/show_bug.cgi?id=12681

For coping with this problem, I have re-implemented the test to allow for an external environment variable to be honoured: DOCSERVER.

If it exists, it overrides the current internal setting to use https://www.idiap.ch. We need to remove once that bug is permanently solved.