simplestorerepo: migrate to in-hg CBOR code This is the only use of thirdparty.cbor outside of a test-* file, so it felt worthwhile to clean it up. Differential Revision: https://phab.mercurial-scm.org/D5520

simplestorerepo: minimal changes required to get this mostly working again I was going to change this code's use of CBOR to use our in-house CBOR code, but discovered it's been broken for a while. This messy change gets it back to a point where it mostly works, I think roughly as well as it ever did. Should we keep this and fix it up the rest of the way, or dump it in favor of the sqlite store? Would this be a good jumping-off point for some sort of union store that could facilitate a cleanup in remotefilelog? Differential Revision: https://phab.mercurial-scm.org/D5519