Add more tests, fix pycurl double handling, revert previous tracking.
* bzrlib/tests/test_http.py: (PredefinedRequestHandler): Renamed from PreRecordedRequestHandler. (PredefinedRequestHandler.handle_one_request): Get the canned response from the test server directly. (ActivityServerMixin): Make it a true object and intialize the attributes in the constructor. Tests can now set the canned_response attribute before querying the server. (TestActivity.setUp, TestActivity.tearDown, TestActivity.get_transport, TestActivity.assertActivitiesMatch): Extracted from test_get to be able to write other tests. (TestActivity.test_has, TestActivity.test_readv, TestActivity.test_post): New tests, all cases should be covered now.
* bzrlib/transport/http/response.py: (RangeFile.__init__, RangeFile.read, handle_response): Revert previous tracking, both http implementations can now report activity from the socket.