lfs: add note messages indicating what store holds the lfs blob The following corruption related patches were written prior to adding the user level cache, and it took awhile to track down why the tests changed. (It generally made things more resilient.) But I think this will be useful to the end user as well. I didn't make it --debug level, because there can be a ton of info coming out of clone/push/pull --debug. The pointers are sorted for test stability. I opted for ui.note() instead of checking ui.verbose and then using ui.write() for convenience, but I see most of this extension does the latter. I have no idea what the preferred form is.

tests: teach `f` to handle sha256 checksums