Grant cppreopts.sh permissions to cleanup if it fails

If cppreopts.sh failed to copy files for some reason it would leave
the temporary files sitting around in the data directory. This changes
the selinux rules so that cppreopts is able to get rid of these
temporary files.

Test: phone boots.
Bug: 63995897
Change-Id: I2a7e654c3a3cee7c9f0be8ba64e40c365eee4cfe