scmutil: fix shortesthexnodeidprefix on Python 3 for 0-prefixed nodes
This fixes test-bookmarks.t on Python 3 (which had regressed.)
Differential Revision: https://phab.mercurial-scm.org/D3926
#!/bin/sh
HGENCODING=UTF-8
export HGENCODING
echo ".. -*- coding: utf-8 -*-" > gendoc.txt
echo "" >> gendoc.txt
LANGUAGE=$1 python "$TESTDIR/../doc/gendoc.py" >> gendoc.txt 2> /dev/null || exit
echo "checking for parse errors"
python "$TESTDIR/../doc/docchecker" gendoc.txt
python "$TESTDIR/../doc/runrst" html gendoc.txt /dev/null