Use CHALLENGE_NONE when VerifyCredential invoked with challenge=0

LSS should generate a challenge if VerifyCredential is invoked
without a challenge. Otherwise, biometric lockout reset will not
work properly.

Bug: 153921881

Test: BiometricPromptDemo, allow device credential, enter password.
      Notice the added log, as well as generateChallenge, resetLockout,
      and revokeChallenge working now.
Change-Id: I0d24afa8b77f0b92b301c1ae53c3e6e8991a1335