Reference pillar defaults to HTTP FileExchange when no FileExchange is specified

When no FileExchange is specified in the reference pillar's ReferenceSettings.xml file, it assumes that a HTTP based (not HTTPS, not FILE) is to be used in all operations.

The result is that when a reference pillar configured as described gets a PutFileRequest with a url based on file:// it will fail with a class cast exception, and report an alarm.

It would be desirable that the reference pillar either does not bind it self to a specific type of file exchange or send an error that indicates that a given protocol is not allowed/accepted/supported rather than failing with a class cast exception.