Separate Change Encryption Password Entry (2 of 2)

This permits the use of a different (hopefully longer and more
complex!) encryption password,
while using a simpler (and easier to type) lockscreen password.

Requires Settings change to give UI for this

(port to cm11 - cyanogen)

Change-Id: Ib54532f92f4f3beb8713fd73e466ae46b7e15f7d