Make test_autopack_rpc_is_used_when_using_hpss raise KnowFailure for CHK repos.
* bzrlib/tests/test_pack_repository.py: (TestSmartServerAutopack.test_autopack_rpc_is_used_when_using_hpss): InterPackToRemotePack explicitely avoid using the autopack RPC, let's try again once fetching has been improved.