Revert "Make this error message similar to the others"

This reverts commit dc1e5ad191.

The new error message was not correct, as it refers to the total balance, not an account.

src/bitcoinrpc.cpp

@@ -1012,7 +1012,7 @@ Value sendmany(const Array& params, bool fHelp)
     if (!fCreated)
     {
         if (totalAmount + nFeeRequired > pwalletMain->GetBalance())
-            throw JSONRPCError(-6, "Account has insufficient funds");
+            throw JSONRPCError(-6, "Insufficient funds");
         throw JSONRPCError(-4, "Transaction creation failed");
     }
     if (!pwalletMain->CommitTransaction(wtx, keyChange))