installd: remove restored ce_data if de_data rollback failed

I think it's clearer (and safer) if failed rollback leaves app devoid of
any data rather that with only ce_data.
LMK if you disagree, I will just abandon this change then. :)

I tried adding a test to make de_rollback fail (while keeping
ce_rollback successful), but failed to.
Only idea I have in mind is to intercept calls to /system/bin/cp, which
doesn't look like a unit test anymore (and also I'm not sure how
feasible it is).

Test: existing tests in installd_service_test pass
Bug: 112431924

Change-Id: I3c6214d70bac682874ea846a01294b5361470f93