store: return just one filename in walk functions
Various walk functions return `(revlog_type, decoded, encoded)` where
decoded could be None. But no-one cares about `encoded` and expects
`unencoded` to be present, except verify (because this can only happen
with old repo formats).
Simplify all this by either failing outright if a decoding a filename
fails (instead of almost certainly failing with a type error due to
treating None as a bytes), or skipping the filename but providing in
an out argument for hg verify.
Differential Revision: https://phab.mercurial-scm.org/D11248
$ cat >> $HGRCPATH << EOF
> [command-templates]
> log="{rev}:{node|short} ({phase}) [{tags} {bookmarks}] {desc|firstline}\n"
> [extensions]
> dirstateparanoidcheck = $TESTDIR/../contrib/dirstatenonnormalcheck.py
> [experimental]
> nonnormalparanoidcheck = True
> [devel]
> all-warnings=True
> EOF
$ mkcommit() {
> echo "$1" > "$1"
> hg add "$1"
> hg ci -m "add $1"
> }
$ hg init testrepo
$ cd testrepo
$ mkcommit a
$ mkcommit b
$ mkcommit c
$ hg status