Update py-cryptography to 1.2.1:

1.2.1 - 2016-01-08
~~~~~~~~~~~~~~~~~~

* Reverts a change to an OpenSSL ``EVP_PKEY`` object that caused errors with
  ``pyOpenSSL``.

1.2 - 2016-01-08
~~~~~~~~~~~~~~~~

* **BACKWARDS INCOMPATIBLE:**
  :class:`~cryptography.x509.RevokedCertificate`
  :attr:`~cryptography.x509.RevokedCertificate.extensions` now uses extension
  classes rather than returning raw values inside the
  :class:`~cryptography.x509.Extension`
  :attr:`~cryptography.x509.Extension.value`. The new classes
  are:

  * :class:`~cryptography.x509.CertificateIssuer`
  * :class:`~cryptography.x509.CRLReason`
  * :class:`~cryptography.x509.InvalidityDate`
* Deprecated support for OpenSSL 0.9.8 and 1.0.0. At this time there is no time
  table for actually dropping support, however we strongly encourage all users
  to upgrade, as those versions no longer receives support from the OpenSSL
  project.
* The :class:`~cryptography.x509.Certificate` class now has
  :attr:`~cryptography.x509.Certificate.signature` and
  :attr:`~cryptography.x509.Certificate.tbs_certificate_bytes` attributes.
* The :class:`~cryptography.x509.CertificateSigningRequest` class now has
  :attr:`~cryptography.x509.CertificateSigningRequest.signature` and
  :attr:`~cryptography.x509.CertificateSigningRequest.tbs_certrequest_bytes`
  attributes.
* The :class:`~cryptography.x509.CertificateRevocationList` class now has
  :attr:`~cryptography.x509.CertificateRevocationList.signature` and
  :attr:`~cryptography.x509.CertificateRevocationList.tbs_certlist_bytes`
  attributes.
* :class:`~cryptography.x509.NameConstraints` are now supported in the
  :class:`~cryptography.x509.CertificateBuilder` and
  :class:`~cryptography.x509.CertificateSigningRequestBuilder`.
* Support serialization of certificate revocation lists using the
  :meth:`~cryptography.x509.CertificateRevocationList.public_bytes` method of
  :class:`~cryptography.x509.CertificateRevocationList`.
* Add support for parsing :class:`~cryptography.x509.CertificateRevocationList`
  :meth:`~cryptography.x509.CertificateRevocationList.extensions` in the
  OpenSSL backend. The following extensions are currently supported:

  * :class:`~cryptography.x509.AuthorityInformationAccess`
  * :class:`~cryptography.x509.AuthorityKeyIdentifier`
  * :class:`~cryptography.x509.CRLNumber`
  * :class:`~cryptography.x509.IssuerAlternativeName`
* Added :class:`~cryptography.x509.CertificateRevocationListBuilder` and
  :class:`~cryptography.x509.RevokedCertificateBuilder` to allow creation of
  CRLs.
* Unrecognized non-critical X.509 extensions are now parsed into an
  :class:`~cryptography.x509.UnrecognizedExtension` object.

(wiz)