contrib: byteify perf.py file
This is done using contrib/byteify-strings.py. There is just one extra change
done to make sure lines don't get longer than 80 chars.
# skip-blame because just b'' prefixes.
Differential Revision: https://phab.mercurial-scm.org/D4422
Set up
$ hg init repo
$ cd repo
Try to import an empty patch
$ hg import --no-commit - <<EOF
> EOF
applying patch from stdin
abort: stdin: no diffs found
[255]
No dirstate backups are left behind
$ ls .hg/dirstate* | sort
.hg/dirstate