Some refactoring around get_canonical_inventory_paths.
* Drop the 'inventory' bit since it doesn't apply to non-inventory trees * Move to working trees; canonicalization currently only matters there, where files can be stored on case-insensitive (VFAT) or normalizing filesystems (i.e. Mac OS X) * Run tests against all working tree formats, including Git, not just InventoryTree ones
This fixes 'bzr mv' and 'bzr rename' for Git.
Merged from https://code.launchpad.net/~jelmer/brz/brz-git-renames/+merge/354952