Updating database to return OUT_OF_KEYS

This updates the assign_attestation_key call to throw the new
OUT_OF_KEYS ResponseCode value if the attestation key pool is out of
keys to assign to new apps.

Test: atest RemoteProvisionerUnitTests
Change-Id: I8ee65bea23acc2daa845648a359be59a78d31e2f
1 file changed