bitcoin-tx: Fix JSON validation of prevtxs

src/bitcoin-tx.cpp

@@ -368,7 +368,7 @@ static void MutateTxSign(CMutableTransaction& tx, const string& flagStr)
     // Add previous txouts given in the RPC call:
     if (!registers.count("prevtxs"))
         throw runtime_error("prevtxs register variable must be set.");
-    UniValue prevtxsObj = registers["privatekeys"];
+    UniValue prevtxsObj = registers["prevtxs"];
     {
         for (unsigned int previdx = 0; previdx < prevtxsObj.count(); previdx++) {
             UniValue prevOut = prevtxsObj[previdx];