statichttprepo: prevent loading dirstate over HTTP on node lookup (
issue5717)
This seems a bit hacky, but works well. There should be no reason that
static-http repo had to load dirstate.
Initially I tried to proxy os.stat() call through vfs so that statichttpvfs
could hook it, but there wasn't a good error value which the statichttpvfs
could return to get around the util.filestat issue.