Issue #749: Add optional SNI support for python2.

SNI support will be enabled for python2 if ndg-httpsclient and pyopenssl are available.

AUTHORS.rst

@@ -125,3 +125,4 @@ Patches and Suggestions
 - Dmitry Medvinsky <me@dmedvinsky.name>
 - Bryce Boe <bbzbryce@gmail.com> @bboe
 - Colin Dunklau <colin.dunklau@gmail.com> @cdunklau
+- Hugo Osvaldo Barrera <hugo@osvaldobarrera.com.ar> @hobarrera

requests/__init__.py

@@ -48,6 +48,12 @@ __author__ = 'Kenneth Reitz'
 __license__ = 'Apache 2.0'
 __copyright__ = 'Copyright 2013 Kenneth Reitz'
 
+# Attempt to enable urllib3's SNI support, if possible
+try:
+    from requests.packages.urllib3.contrib import pyopenssl
+    pyopenssl.inject_into_urllib3()
+except ImportError:
+    pass
 
 from . import utils
 from .models import Request, Response, PreparedRequest

setup.py

@@ -20,6 +20,7 @@ packages = [
     'requests.packages.charade',
     'requests.packages.urllib3',
     'requests.packages.urllib3.packages',
+    'requests.packages.urllib3.contrib',
     'requests.packages.urllib3.packages.ssl_match_hostname'
 ]