[swinog] SWITCH Sourceforge mirror available again

Over the past couple of weeks, you might have noticed that for Sourceforge downloads, "Lausanne, Switzerland (SWITCH)" (switch.dl.sourceforge.net) was no longer listed as a mirror option. The reason was that the disk array of the server had become too small to hold the entire Sourceforge mirror dataset (because of all the binary stuff I guess - this thing should be called ".iso-forge" :-). We have now replaced it with a new server with larger disks, so now it should be fully included in the Sourceforge download mirror set.

Note that, like mirror.switch.ch and many other of our services, this is reachable over IPv6 in addition to IPv4.

Now go and test that thing :-)