Delta image between rootfs before & after !9 have `/android` in `removed`

The delta generator treats each entry (with and without ./) in the tarball separately, which means system/./android is a different entry than system/android. And when the latter is removed in !9 (merged), the delta generator dutifully put that in the removed file, resulting in /android being deleted from the final device's partition. That, as you might have guessed, results in unbootable device.

I think we'll have to canonicalize every path before we consider which file is removed.