ubuntu_kvm_smoke_test fail with FIPS kernel (dsa keys not allowed)

[Po-Hsu Lin]

After enabling the fips-dev ppa and using user-space tool there. The ubuntu_kvm_smoke_test starts failing with:
 + uvt-kvm create bjf-test release=bionic arch=s390x
 DSA keys are not allowed in FIPS mode

Take a closer look inside /usr/lib/python2.7/dist-packages/uvtool/libvirt/kvm.py, which calls uvtool.ssh.generate_ssh_host_keys() from /usr/lib/python2.7/dist-packages/uvtool/ssh.py

From ssh.py, you will find it will try to generate 4 different key types, includes "dsa":

KEY_TYPES = ['rsa', 'dsa', 'ecdsa', 'ed25519']
...
def generate_ssh_host_keys():
    cloud_init_result = {}
    known_hosts_result = []
    tmp_dir = tempfile.mkdtemp(prefix='uvt-kvm.sshtmp')
    try:
        for key_type in KEY_TYPES:
            private_path = os.path.join(tmp_dir, key_type)
            _keygen(key_type, private_path)

[Po-Hsu Lin (cypressyew)]

We will need to backport fix for https://bugs.launchpad.net/bugs/1936473 to uvtool on bionic.
https://code.launchpad.net/~paelzer/uvtool/+git/uvtool/+merge/405796