Move rild to the core class.

Changes in init.stingray.rc now prevent rild from making sockets
or named pipes on /data.  Now that rild no longer prevents /data
from being unmounted, we can put it in the core class, which doesn't
restart when we enable encryption.  This speeds up the boot by 20+
seconds.

Change-Id: I71c426dab1b725e401116234167d41c7ccd958c1