fetch: do not count inactive branches when inferring a merge
The fetch extension would erroneously consider inactive branches when
inferring which branches to merge. It now considers only active
branches.
#!/bin/sh
hg init repo
cd repo
touch foo
hg ci -Am 'add foo'
hg up -C null
# this should be stored as a delta against rev 0
echo foo bar baz > foo
hg ci -Am 'add foo again'
hg debugindex .hg/store/data/foo.i