Temporarily downgrade to policy version number

Temporarily move from policy version 30 to 29 until device kernels
and prebuilts are all upgraded to the accepted upstream version of
the selinux ioctl command whitelisting code.

(cherry picked from commit 89765083)

Bug: 22846070

Change-Id: I31d1e80aaee164cf41a2f01c6ca846a000898ef4