Test the http redirection at the request level even if it's not used anymore, so far.
* bzrlib/transport/http/_urllib2_wrappers.py (HTTPRedirectHandler.http_error_302): Renamed from http_error_30x. (HTTPRedirectHandler.http_error_301): Deleted. Finally, that's the easiest way to fix bug #88780 :) In retrospect, that code was a first attempt to handle this whole redirection handling by providing the final target to the first request. This is not needed anymore.
* bzrlib/tests/test_http.py: (RedirectedRequest, TestHTTPSilentRedirections_urllib): Test the _urllib2_wrappers redirection at the request level.
* bzrlib/tests/HTTPTestUtil.py: (RedirectRequestHandler.parse_request): Delegate the redirection handling to the test_case_server. (HTTPServerRedirecting.is_redirected): Handle redirections by searching a matching directive. (HTTPServerRedirecting.redirect_to): Redefined to use the nre redirections definitions.