tests: test coverage for empty graft A future change will add a warning to the quiet rebase.

largefiles: drop the unfiltered repo usage in overridepurge() Now that repoview supports replacing methods, we don't need this hack.

repoview: allow methods on the proxy class to be replaced It doesn't seem to be a common idiom for repo instances, but the status() method is replaced in largefiles' purge() override. Since __setattr__ is implemented in repoview to setattr() on the unfiltered repo, the replacement method wouldn't get called unless it was invoked with the unfiltered repo, because the filtered repo remains unchanged. Since this doesn't seem to be commonly used, I didn't bother to filter out methods that perhaps shouldn't be replaced, such as changelog().