evolve: use right value for branch name when finding branch heads
subbranch already formatted as "branchname:topicname", again appending it
with ":topicname" doesn't not make sense.
It's a little bit surprising that no tests fails though.
#!/bin/bash
set -euox pipefail
unset GREP_OPTIONS
NOTOPIC="--config experimental.topic-mode=ignore"
compatbranches=`hg branches --quiet | grep 'mercurial-' | grep -v ':' | sort -n --reverse`
prev='stable'
for branch in $compatbranches; do
hg up $branch
hg merge $prev
hg commit -m "test-compat: merge $prev into $branch"
prev=$branch
done