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

public/cppreopts.te

@@ -9,7 +9,7 @@ type cppreopts_exec, exec_type, file_type;
 
 # Allow cppreopts copy files into the dalvik-cache
 allow cppreopts dalvikcache_data_file:dir { add_name remove_name search write };
-allow cppreopts dalvikcache_data_file:file { create getattr open read rename write };
+allow cppreopts dalvikcache_data_file:file { create getattr open read rename write unlink };
 
 # Allow cppreopts to execute itself using #!/system/bin/sh
 allow cppreopts shell_exec:file rx_file_perms;