pipe auth token through confirm and set password

ConfirmDeviceCredentialsActivity and ChooseLockGeneric now understand
CLSH.EXTRA_KEY_HAS_CHALLENGE and CLSH.EXTRA_KEY_CHALLENGE in their
launching intents. If present, they return a hw_auth_token_t verifying
the challenge passed in as a field in keyed by
CLSH.EXTRA_KEY_CHALLENGE_TOKEN in their result intents.

Change-Id: I0b4e02b6a798a9e57d02522880a180dffadfcde1