BUG/MINOR: server: Don't warn fallback IP is used during init-addr resolution

When a fallback IP address is provided in the list of methods to use to
resolve the server address, a warning is emitted if previous methods
failed. The aim is to inform this address will be used for the
server. However, it is valid use-case. It is the expected behavior. There is
no reason to emit a warning. Having a message during HAProxy startup to
inform the fallback IP address will be used is probably a good idea. But it
should be a notice not a warning. Otherwise, checking the configuration
validity will always failed, just like starting HAProxy in zero-warning
mode while the option was set on purpose.

This patch should fix the issue #2627. It must be backported to all stable
versions.

src/server.c

@@ -4954,8 +4954,8 @@ static int srv_iterate_initaddr(struct server *srv)
 		case SRV_IADDR_IP:
 			_srv_set_inetaddr(srv, &srv->init_addr);
 			if (return_code) {
-				ha_warning("could not resolve address '%s', falling back to configured address.\n",
-					   name);
+				ha_notice("could not resolve address '%s', falling back to configured address.\n",
+					  name);
 			}
 			goto out;