cryptography-1.3 breaks unit tests

With cryptography 1.3, the unit tests are failing with:

Traceback (most recent call last):
  File "os_cloud_config/tests/test_keystone_pki.py", line 36, in test_create_ca_and_signing_pairs
    self.assertTrue(ca_key.check())
  File "/home/fedora/os-cloud-config/.tox/py27/lib/python2.7/site-packages/OpenSSL/crypto.py", line 243, in check
    if _lib.EVP_PKEY_type(self._pkey.type) != _lib.EVP_PKEY_RSA:
AttributeError: '_cffi_backend.CDataGCP' object has no attribute 'type'

I've opened https://github.com/pyca/cryptography/issues/2837 upstream to get this fixed. In the meantime we may need to exclude cryptography 1.3 in global requirements.

logstash query: http://logstash.openstack.org/#dashboard/file/logstash.json?query=build_status%3A%20FAILURE%20AND%20message%3A%20%5C%22_cffi_backend.CDataGCP%5C%22

Appears to be affecting os-cloud-config and neutron-lbaas right now.