Merge branch 'dt/cache-tree-repair'

Add a few more places in "commit" and "checkout" that make sure that the cache-tree is fully populated in the index. * dt/cache-tree-repair: cache-tree: do not try to use an invalidated subtree info to build a tree cache-tree: Write updated cache-tree after commit cache-tree: subdirectory tests test-dump-cache-tree: invalid trees are not errors cache-tree: create/update cache-tree on checkout