Allow use of rules Policy driver

With the implementation of bp abstract-base-class-drivers , the
"rules" Policy driver couldn't be used anymore because it didn't
implement the methods in the base class.

This change makes it so that the rules Policy driver can be used
again.

bp abstract-base-class-drivers

Change-Id: Ia2a5d42007f7480c2757932afcde35f121e05cab
Merge "Allow use of rules Policy driver"