Fix KeyAttestation Cts test failure in unlocked devices

This CL sets the verified boot key in attestation parameters to all
zeros of 32 bytes when the boot loader passes an empty
verified boot key.

Bug: 192634248
Test: atest android.keystore.cts.KeyAttestationTest#testEcAttestation
      atest android.keystore.cts.KeyAttestationTest#testRsaAttestation
Change-Id: I9ddbdc55e4e2b842885de278f165a6347926e8a6
1 file changed