Revert "SELinux: su: update policies"

This reverts commit 04fd9192b05ae2655560a444711fe8859430f439.

Change-Id: I69e51fb6c151a48972cf81947c1c59c6f26f60e9
selinux: Workaround for devices with PR_SET_NO_NEW_PRIVS enforcement

PR_SET_NO_NEW_PRIVS blocks domain transitions from within app_process,
unless the new domain is bounded by the app's context. So we can't
switch to a domain that has perms not available to untrusted_app :(

This means any app can talk to the daemon, bypassing the su executable
client. That's not a good thing, and needs to be resolved.

Change-Id: I85b74f90b8737caaa193a0555b5262e7392519b2