SSH and session tests are failing

[asmacdo]

For now I am xfailing these tests to get #584 merged.

Curiously, I hit this error earlier and was able to solve it by pinning paramiko=2.8.1. The issue was that paramiko erroniously treats RSA keys as DSA keys. fabric/fabric#2182

Pinning solved this issue elsewhere, perhaps the problem is that one of our external deps is vendoring an older paramiko?

FAILED reproman/resource/tests/test_ssh.py::test_ssh_class - ValueError: q must be exactly 160, 224, or 256 bits long
FAILED reproman/resource/tests/test_ssh.py::test_ssh_resource - ValueError: q must be exactly 160, 224, or 256 bits long

ERROR reproman/resource/tests/test_session.py::test_session_ssh[SSHSession] - ValueError: q must be exactly 160, 224, or 256 bits long
ERROR reproman/resource/tests/test_session.py::test_session_ssh[PTYSSHSession] - ValueError: q must be exactly 160, 224, or 256 bits long