topic: drop compat.successorssets(), it's not used
The only place in topics that uses successorssets function is in evolvebits.py,
and it's using that function from obsutil directly.
. $TESTDIR/testlib/common.sh
cat >> $HGRCPATH <<EOF
[ui]
interactive = true
[phases]
publish=False
[extensions]
evolve =
[experimental]
evolution.effect-flags = yes
EOF
sync() {
hg pull -R $TESTTMP/server . -q
}