log: log RPC port on startup

I just spent a few hours trying to figure out why "18444" wasn't getting
me to regtest's RPC server. I'm not the sharpest tool in the shed, but I
was maybe understandably confused because "Bound to
127.0.0.1:18445" appears in the logs, which I assumed was the P2P port.

This change logs the RPC listening address, which seems like a basic
piece of information that shouldn't be buried in debug logs.

Author: jamesob

src/httpserver.cpp

@@ -320,7 +320,7 @@ static bool HTTPBindAddresses(struct evhttp* http)
 
     // Bind addresses
     for (std::vector<std::pair<std::string, uint16_t> >::iterator i = endpoints.begin(); i != endpoints.end(); ++i) {
-        LogPrint(BCLog::HTTP, "Binding RPC on address %s port %i\n", i->first, i->second);
+        LogPrintf("Binding RPC on address %s port %i\n", i->first, i->second);
         evhttp_bound_socket *bind_handle = evhttp_bind_socket_with_handle(http, i->first.empty() ? nullptr : i->first.c_str(), i->second);
         if (bind_handle) {
             CNetAddr addr;