Test parametrization for protocol versions achieved. Tests are failing :)

* bzrlib/tests/test_http_implementations.py:
(TransportAdapter, TransportProtocolAdapter,
TransportProtocolAuthenticationAdapter): Adpaters for the
combinations we care about.
(load_tests): List the classes that needs to be adpated and apply
the associated parametrization.
(TestPost.test_post_body_is_received): Don't use
transport.get_transport since we already know the transport class
we want to test.
(TestSpecificRequestHandler.create_transport_readonly_server,
LimitedRangeHTTPServer.__init__,
TestLimitedRangeRequestServer.create_transport_readonly_server,
TestProxyHttpServer.create_transport_secondary_server,
TestHTTPRedirections.create_transport_secondary_server,
TestHTTPSilentRedirections.create_transport_secondary_server,
TestAuth.create_transport_readonly_server,
TestAuth.create_transport_readonly_server): Add protocol_version
parameter to constructors.

* bzrlib/tests/http_utils.py:
(HTTPServerRedirecting, AuthServer, DigestAuthServer,
HTTPBasicAuthServer, HTTPDigestAuthServer, ProxyBasicAuthServer,
ProxyDigestAuthServer): Add protocol_version parameter to
constructors.