branchmap: _updatebranchmap does not need to be filtered
The `_updatebranchmap` method on repo does not need to be filtered as all
callers are already handling filtering themself.
The fact it is filtered may had even lead to buggy behaviors, but by chances the method
make very sparse use of the repo object.
$ "$TESTDIR/hghave" unix-permissions || exit 80
$ hg init a
$ echo a > a/a
$ hg -R a ci -A -m a
adding a
$ hg clone a b
updating to branch default
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ echo b > b/b
$ hg -R b ci -A -m b
adding b
$ chmod 100 a/.hg/store
$ hg -R b push a
pushing to a
abort: could not lock repository a: Permission denied
[255]
$ chmod 700 a/.hg/store