Fix compile error

src/wallet/wallet.cpp

@@ -3122,7 +3122,7 @@ std::vector<uint256> CWallet::ResendWalletTransactionsBefore(int64_t nTime)
             continue;
 
         // Do not relay expired transactions, to avoid other nodes banning us
-        if (wtx.nExpiryHeight > 0 && wtx.nExpiryHeight < chainActive.LastTip->GetHeight()) {
+        if (wtx.nExpiryHeight > 0 && wtx.nExpiryHeight < chainActive.LastTip()->GetHeight()) {
             fprintf(stderr,"%s: ignoring expired tx %s\n", wtx.GetHash().ToString().c_str() );
             // TODO: should we call EraseFromWallet(wtx) right here?
             continue;