localrepo/branchcache: remove lbranchmap(), convert users to use utf-8 names
We don't need a "local-charset" aware branchmap() function, we can convert the
names when needed during the output.
#!/bin/sh
mkdir t
cd t
hg init
echo a > a
hg add a
hg commit -m test -d "1000000 0"
rm .hg/requires
hg tip
echo indoor-pool > .hg/requires
hg tip
true