Since the destination for all backed up files during an installation was
/tmp, all files sharing a name (like the full_model.bin files from
the various face detectors) ended up being restored as copies of
the last such file, effectively breaking the backup.
As a fix, when backing up files, use the entire original path to make
sure they're kept separate and restorable.
Change-Id: I399f7a9433a225871d97e0ecaeb051a90e68696b
2dc7045f2b