Add a fake https server and test facilities.

* bzrlib/transport/http/_urllib2_wrappers.py:
(HTTPSConnection.connect_to_origin): Disable ssl wrapping temporarily.

* bzrlib/transport/http/_urllib.py:
(get_test_permutations): Add https tests if a server is available.

* bzrlib/tests/http_server.py:
(TestingHTTPServer): Fix typo.
(HttpServer.get_bogus_url): Use _url_protocol.

* bzrlib/tests/__init__.py:
(_HTTPSServerFeature): Define a feature since an https test server
will have dependencies.