Our "fix" to https://bugs.debian.org/909700 in
d8fc9f28 just avoided testing the
actual typical default output of ssh-keygen.

While this was fair to do in tests/keytrans, where it is exercised on
pem2openpgp (which is explicitly defined as only accepting PEM input),
this is inappropriate for testing monkeysphere in general.

So now, the test suite breaks again, but we need to provide a proper
fix.