Add another ssl-related keyword to the httplib2 intercept

Should probably consider changing it to kwargs, but this way it is
explicit about what args are being dropped. Add a note to the docs
to indicate this is the case (it's always been true).

docs/httplib2.rst

@@ -3,6 +3,11 @@ httplib2_intercept
 
 .. automodule:: wsgi_intercept.httplib2_intercept
 
+.. note:: No effort is made to pass SSL certificate or version
+          information to the the underlying ``HTTPSConnection``. The
+          assumption is that wsgi-intercept is testing the behavior
+          of the application, not the connection.
+
 Example:
 
 .. testcode:: 

wsgi_intercept/httplib2_intercept.py

@@ -32,7 +32,8 @@ class HTTPS_WSGIInterceptorWithTimeout(HTTPSInterceptorMixin,
         HTTPSConnectionWithTimeout):
     def __init__(self, host, port=None, strict=None, timeout=None,
             proxy_info=None, ca_certs=None, source_address=None,
-            disable_ssl_certificate_validation=False):
+            disable_ssl_certificate_validation=False,
+            ssl_version=None):
 
         # ignore proxy_info and ca_certs
         # In Python3 strict is deprecated