Fix two warnings for comparison between signed and unsigned

src/wallet/rpcwallet.cpp

@@ -2457,7 +2457,7 @@ UniValue fundrawtransaction(const UniValue& params, bool fHelp)
     if (origTx.vout.size() == 0)
         throw JSONRPCError(RPC_INVALID_PARAMETER, "TX must have at least one output");
 
-    if (changePosition != -1 && (changePosition < 0 || changePosition > origTx.vout.size()))
+    if (changePosition != -1 && (changePosition < 0 || (unsigned int)changePosition > origTx.vout.size()))
         throw JSONRPCError(RPC_INVALID_PARAMETER, "changePosition out of bounds");
 
     CMutableTransaction tx(origTx);

src/wallet/wallet.cpp

@@ -2232,7 +2232,7 @@ bool CWallet::CreateTransaction(const vector<CRecipient>& vecSend, CWalletTx& wt
                             // Insert change txn at random position:
                             nChangePosInOut = GetRandInt(txNew.vout.size()+1);
                         }
-                        else if (nChangePosInOut > txNew.vout.size())
+                        else if ((unsigned int)nChangePosInOut > txNew.vout.size())
                         {
                             strFailReason = _("Change index out of range");
                             return false;