try SLCS https service in wget scripts

[alaniwi]

I gather that the SLCS https service is now integrated with the installer, although at time of writing believed to be only deployed at CEDA.

It would be worth updating the wget scripts (perhaps once it is more widely deployed) to allow for this as an option to try if myproxy fails.

In particular, some users seem to have outbound firewall restrictions affecting "non-standard" ports such as myproxy.

[sashakames]

Under the current architecture, the SLCS-generated certificate is not a drop-in replacement for a myproxy cert. But we can all look forward to the current auth filter replacement.