Give SD cards their own keys and modes.

When we set up encryption on real volumes - not just /data - we should
give them their own keys, so that these keys can be deleted when the
volume is forgotten. Also, we must choose the encryption modes
differently, since ICE encryption which works on /data may not work on
such volumes.

Bug: 25861755
Test: boot device, add SD card, check modes.
Change-Id: I354cd651757c3566dba046ae99d324833ad9b0e5
1 file changed