effetflag: detect other meta (extra) changes
Check other changeset meta other than branch and *_source and if there is a
change, set the METACHANGED effect flag.
Add a test for this scenario with a topic change.
#!/bin/sh
# This file holds logic that is used in many tests.
# It can be called in a test like this:
# $ . "$TESTDIR/testlib/topic_setup.sh"
# Enable obsolete markers and enable extensions
cat >> $HGRCPATH << EOF
[experimental]
evolution=createmarkers,exchange
[extensions]
rebase=
EOF
echo "topic=$(echo $(dirname $TESTDIR))/hgext3rd/topic" >> $HGRCPATH