typing: suppress a false error in mercurial/revlogutils/docket.py on py2
`ord()` wants bytes or str on py3, so I'm guessing it got confused by passing a
single byte instead of a one byte string. But this seems to work on 2.7.18
anyway.
Differential Revision: https://phab.mercurial-scm.org/D10876
$ hg init
$ echo 123 > a
$ hg add a
$ hg commit -m "first" a
$ mkdir sub
$ echo 321 > sub/b
$ hg add sub/b
$ hg commit -m "second" sub/b
$ cat sub/b
321
$ hg co 0
0 files updated, 0 files merged, 1 files removed, 0 files unresolved
$ cat sub/b 2>/dev/null || echo "sub/b not present"
sub/b not present
$ test -d sub || echo "sub not present"
sub not present