tests/test-1102

branch heads: fix regression introduced in e67e5b60e55f (issue1726)

For merge nodes it is not adequate to only check a single possible
branch head for whether it is an ancestor of the latest head, but it
needs to be done for each possible branch head.

#!/bin/sh

rm -rf a
hg init a
cd a
echo a > a
hg ci -Am0
hg tag t1 # 1
hg tag --remove t1 # 2

hg co 1
hg tag -r0 t1
hg tags