Unit test for allowing use of hgrc in clone, addresses #3

Created originally on Bitbucket by jongunnip (Jon Gunnip)

Was already merged in Bitbucket before import, marked as merged by the import user

I used Martin's suggestion to use a small extension found in https://bitbucket.org/mirror/mercurial/src/55982f62651f/tests/test-http.t#cl-114 that would require auth for requests to an hg serve'd repository.

I didn't include the extension in javahg-test because I wasn't sure that it would not affect other tests.