The ssh setup first runs ssh to the real hostname, to probe if a ssh key is
needed. If one is, it generates a mangled hostname that uses a key. This
mangled hostname was being used to ssh into the server to set up the key.
But if the server already had the key set up, and it was locked down, the
setup would fail. This changes it to use the real hostname when sshing in
to set up the key, which avoids the problem.
Note that it will redundantly set up the key on the ssh server. But it's
the same key; the ssh key generation code uses the key if it already
exists.