Hopefully fix funky SELinux labels.

We've seen reports of cases where DE storage cache directories are
missing the SELinux category information, so explicitly offer to
restorecon those directories to fix the labels.

This matches what we're already doing for CE storage.

Test: builds, boots
Bug: 35991539
Change-Id: I0eb6df801e933fbb005e3f8fdfe57a4e5ce3313d