send the specified hostname in the HTTP URI

dig was not working with a server with offloaded TLS;
this turned out to be because it was sending the URI as
"https://<address>/dns-query", not "https://<name>/dns-query".
using userarg instead of servname fixes the problem. (incidentally
also corrected logged output to use the hostname when available.)

bin/dig/dig.c

@@ -359,7 +359,7 @@ received(unsigned int bytes, isc_sockaddr_t *from, dig_query_t *query) {
 		} else {
 			proto = "UDP";
 		}
-		printf(";; SERVER: %s(%s) (%s)\n", fromtext, query->servname,
+		printf(";; SERVER: %s(%s) (%s)\n", fromtext, query->userarg,
 		       proto);
 		time(&tnow);
 		(void)localtime_r(&tnow, &tmnow);

bin/dig/dighost.c

@@ -2800,7 +2800,7 @@ start_tcp(dig_query_t *query) {
 		} else if (query->lookup->https_mode) {
 			char uri[4096] = { 0 };
 			snprintf(uri, sizeof(uri), "https://%s:%u%s",
-				 query->servname, (uint16_t)port,
+				 query->userarg, (uint16_t)port,
 				 query->lookup->https_path);
 
 			if (!query->lookup->http_plain) {

lib/isc/netmgr/http.c

@@ -1846,7 +1846,7 @@ isc_nm_listenhttp(isc_nm_t *mgr, isc_nmiface_t *iface, int backlog,
 /*
  * In DoH we just need to intercept the request - the response can be sent
  * to the client code via the nmhandle directly as it's always just the
- * http * content.
+ * http content.
  */
 static void
 http_callback(isc_nmhandle_t *handle, isc_result_t result, isc_region_t *data,