Add RPC error code for non-deterministic wallet

src/wallet/wallet_rpc_server.cpp

@@ -1577,6 +1577,7 @@ namespace tools
         epee::wipeable_string seed;
         if (!m_wallet->get_seed(seed))
         {
+            er.code = WALLET_RPC_ERROR_CODE_NON_DETERMINISTIC;
             er.message = "The wallet is non-deterministic. Cannot display seed.";
             return false;
         }

src/wallet/wallet_rpc_server_error_codes.h

@@ -73,3 +73,4 @@
 #define WALLET_RPC_ERROR_CODE_BAD_SIGNED_TX_DATA     -40
 #define WALLET_RPC_ERROR_CODE_SIGNED_SUBMISSION      -41
 #define WALLET_RPC_ERROR_CODE_SIGN_UNSIGNED          -42
+#define WALLET_RPC_ERROR_CODE_NON_DETERMINISTIC      -43