Update entitlement unit tests

This patch updates the entitlement keys in the sample code and in the
unit tests to use AES 256.

test/oec_device_features.cpp

@@ -171,7 +171,6 @@ void DeviceFeatures::PickDerivedKey() {
   }
   if (uses_keybox) {
     // If device uses a keybox, try to load the test keybox.
-    // TODO(jfore): Update to pass in parameters.
     if (OEMCrypto_ERROR_NOT_IMPLEMENTED != OEMCrypto_LoadTestKeybox(NULL, 0)) {
       derive_key_method = LOAD_TEST_KEYBOX;
     } else if (IsTestKeyboxInstalled()) {