Add unimplemented private transaction type

- https://entethalliance.github.io/client-spec/spec.html#sec-extensions-json-rpc

ethereum/jsonrpc/src/main/java/tech/pegasys/pantheon/ethereum/jsonrpc/internal/methods/privacy/EeaSendRawTransaction.java

@@ -12,6 +12,7 @@
  */
 package tech.pegasys.pantheon.ethereum.jsonrpc.internal.methods.privacy;
 
+import static java.nio.charset.StandardCharsets.UTF_8;
 import static tech.pegasys.pantheon.ethereum.jsonrpc.JsonRpcErrorConverter.convertTransactionInvalidReason;
 
 import tech.pegasys.pantheon.ethereum.core.Transaction;
@@ -77,6 +78,13 @@ public JsonRpcResponse response(final JsonRpcRequest request) {
       return new JsonRpcErrorResponse(request.getId(), JsonRpcError.INVALID_PARAMS);
     }
 
+    if (!privateTransaction
+        .getRestriction()
+        .equals(BytesValue.wrap("unrestricted".getBytes(UTF_8)))) {
+      return new JsonRpcErrorResponse(
+          request.getId(), JsonRpcError.UNIMPLEMENTED_PRIVATE_TRANSACTION_TYPE);
+    }
+
     final Transaction transaction;
     try {
       transaction = handlePrivateTransaction(privateTransaction);

ethereum/jsonrpc/src/main/java/tech/pegasys/pantheon/ethereum/jsonrpc/internal/response/JsonRpcError.java

@@ -84,7 +84,8 @@ public enum JsonRpcError {
   UNAUTHORIZED(-40100, "Unauthorized"),
 
   // Private transaction errors
-  ENCLAVE_IS_DOWN(-32000, "Enclave is down");
+  ENCLAVE_IS_DOWN(-50100, "Enclave is down"),
+  UNIMPLEMENTED_PRIVATE_TRANSACTION_TYPE(-50100, "Unimplemented private transaction type");
 
   private final int code;
   private final String message;