port 1.5.1 changelog to master (#3166)

diff --git a/CHANGELOG.rst b/CHANGELOG.rst
index 2e38ae5..692831a 100644
--- a/CHANGELOG.rst
+++ b/CHANGELOG.rst
@@ -26,6 +26,17 @@
   :meth:`~cryptography.x509.random_serial_number`.
 
 
+1.5.1 - 2016-09-22
+~~~~~~~~~~~~~~~~~~
+
+* Updated Windows and OS X wheels to be compiled against OpenSSL 1.0.2i.
+* Resolved a ``UserWarning`` when used with cffi 1.8.3.
+* Fixed a memory leak in name creation with X.509.
+* Added a workaround for old versions of setuptools.
+* Fixed an issue preventing ``cryptography`` from compiling against
+  OpenSSL 1.0.2i.
+
+
 1.5 - 2016-08-26
 ~~~~~~~~~~~~~~~~