branchcache: store filtered hash and obsolete hash independently for V3
This will avoid the bug covered in tests/test-branches-obsolete.t when we stop
storing all heads explicitly in V3.
#require test-repo jshint hg10
$ . "$TESTDIR/helpers-testrepo.sh"
run jshint on all tracked files ending in .js except vendored dependencies
$ cd "`dirname "$TESTDIR"`"
$ testrepohg locate 'set:**.js' \
> 2>/dev/null \
> | xargs jshint