Log Message:
Updated py-cryptography to 1.9.

1.9 - 2017-05-29
~~~~~~~~~~~~~~~~

* **BACKWARDS INCOMPATIBLE:** Elliptic Curve signature verification no longer
  returns ``True`` on success. This brings it in line with the interface's
  documentation, and our intent. The correct way to use
  :meth:`~cryptography.hazmat.primitives.asymmetric.ec.EllipticCurvePublicKey.verify`
  has always been to check whether or not
  :class:`~cryptography.exceptions.InvalidSignature` was raised.
* **BACKWARDS INCOMPATIBLE:** Dropped support for macOS 10.7 and 10.8.
* **BACKWARDS INCOMPATIBLE:** The minimum supported PyPy version is now 5.3.
* Python 3.3 support has been deprecated, and will be removed in the next
  ``cryptography`` release.
* Add support for providing ``tag`` during
  :class:`~cryptography.hazmat.primitives.ciphers.modes.GCM` finalization via
  \ 
:meth:`~cryptography.hazmat.primitives.ciphers.AEADDecryptionContext.finalize_wi \ 
th_tag`.
* Fixed an issue preventing ``cryptography`` from compiling against
  LibreSSL 2.5.x.
* Added
  \ 
:meth:`~cryptography.hazmat.primitives.asymmetric.ec.EllipticCurvePublicKey.key_ \ 
size`
  and
  \ 
:meth:`~cryptography.hazmat.primitives.asymmetric.ec.EllipticCurvePrivateKey.key \ 
_size`
  as convenience methods for determining the bit size of a secret scalar for
  the curve.
* Accessing an unrecognized extension marked critical on an X.509 object will
  no longer raise an ``UnsupportedExtension`` exception, instead an
  :class:`~cryptography.x509.UnrecognizedExtension` object will be returned.
  This behavior was based on a poor reading of the RFC, unknown critical
  extensions only need to be rejected on certificate verification.
* The CommonCrypto backend has been removed.
* MultiBackend has been removed.
* ``Whirlpool`` and ``RIPEMD160`` have been deprecated.