migrate cupani/git-rw to the ganeti cluster, triggering an IP address change

i will soon migrate cupani AKA git-rw.torproject.org to the new ganeti cluster. this will involve an IP address change which might affect the service.

please let me know if there are any problems you can think of. in particular, do let me know if any internal (inside the server) or external (outside the server) services hardcodes the IP address of cupani.

thanks!