tests/testlib/obsmarker-common.sh

exchange: switch to usual way of testing for bundle2-ness

We used safehasattr() in one place, but we use isinstance() for this
everywhere else, so switch to the latter.

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