fingerprint: send cancel-message to system

Android expects a FINGERPRINT_ERROR_CANCELED error-message if a
fingerprint authentication-requested was cancelled.

As bauth doesn't deliver such a message on its own, we use the
already notify-wrapper to send a message to Android if the
authentication was cancelled by bauth to allow a proper operation
of the fingerprint-service.

Some devices (hero, hero2) with the fingerprint scanner embedded in
the home button need this for the "config_fingerprintWakeAndUnlock"
option to work reliably.

Change-Id: Id5ec866a7608885925687a1927e0e6085e9b6cff
Ref: BUGBASH-1422