Merge #696: sendtomainchain with pak and subtract fee from output fix

adedc7f fix HelpExamplRPC port for liquidv1 vs bitcoin mainnet (Gregory Sanders)
d35bf08 Fix sendtomainchain with pak when subtracting fee from output (Gregory Sanders)

Pull request description:

  resolves #695

  and also fixes RPC port in help

  needs backport to 0.17/0.18

Tree-SHA512: fb5414264a3fc70320b2e25261435a60383c4bf7c2c7f2d6381a862a1c89b2a97f824da412d21cf2e827d02e40e54dde214de471aad9a54c7f3c06ec98d6d840

Author: stevenroose

src/rpc/server.cpp

@@ -578,7 +578,7 @@ std::string HelpExampleCli(const std::string& methodname, const std::string& arg
 std::string HelpExampleRpc(const std::string& methodname, const std::string& args)
 {
     return "> curl --user myusername --data-binary '{\"jsonrpc\": \"1.0\", \"id\":\"curltest\", "
-        "\"method\": \"" + methodname + "\", \"params\": [" + args + "] }' -H 'content-type: text/plain;' http://127.0.0.1:8332/\n";
+        "\"method\": \"" + methodname + "\", \"params\": [" + args + "] }' -H 'content-type: text/plain;' http://127.0.0.1:7041/\n";
 }
 
 void RPCSetTimerInterfaceIfUnset(RPCTimerInterface *iface)

src/wallet/rpcwallet.cpp

@@ -5195,7 +5195,7 @@ UniValue sendtomainchain_pak(const JSONRPCRequest& request)
 
     bool subtract_fee = false;
     if (request.params.size() > 2) {
-        subtract_fee = request.params[1].get_bool();
+        subtract_fee = request.params[2].get_bool();
     }
 
     CPAKList paklist = g_paklist_blockchain;

test/functional/feature_pak.py

@@ -410,6 +410,10 @@ def compare(actual, expected):
                     raise Exception("Found unexpected peg-out output")
         assert(peg_out_found)
 
+        # Test that subtracting fee from output works
+        self.nodes[i_pak1].sendtomainchain("", self.nodes[i_pak1].getbalance()["bitcoin"], True)
+        assert_equal(self.nodes[i_pak1].getbalance()["bitcoin"], 0)
+
         # TODO: create rawsendtomainchain to do transaction surgery for testing
 
 if __name__ == '__main__':