py3: use .startswith() instead of bytes[0]
Doing bytes[0] will return the ascii value of that position which breaks
comparison with a bytechar.
This makes test-absorb.t work again on py3.
Differential Revision: https://phab.mercurial-scm.org/D6508
mkcommit() {
echo "$1" > "$1"
hg add "$1"
hg ci -m "$1"
}
getid() {
hg log --hidden --template '{node}\n' --rev "$1"
}
cat >> $HGRCPATH <<EOF
[alias]
debugobsolete=debugobsolete -d '0 0'
EOF