test-dirstate-version-fallback: future-proof the test for a different default
Dirstate-v2 will become the default at some point, which would cause this
test to fail. Let's save someone else the headache later.
{
"conduit_uri": "https://phab.mercurial-scm.org/api",
"phabricator.uri": "https://phab.mercurial-scm.org/",
"repository.callsign": "HG",
"arc.land.onto.default": "@",
"base": "hg:.^"
}