[gssdp] client: Fix Server: header default

[Jens Georg <jensgeorg src gnome org>]

commit ed5a017c5ed26a3c887c0d100ee0239dec563ade
Author: Jens Georg <mail jensge org>
Date:   Mon Jan 28 22:01:35 2019 +0100

    client: Fix Server: header default

 libgssdp/gssdp-client.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/libgssdp/gssdp-client.c b/libgssdp/gssdp-client.c
index ba4f44e..d290fcb 100644
--- a/libgssdp/gssdp-client.c
+++ b/libgssdp/gssdp-client.c
@@ -215,7 +215,7 @@ gssdp_client_initable_init (GInitable                   *initable,
         }
 
         /* Generate default server ID */
-        if (priv->server_id != NULL) {
+        if (priv->server_id == NULL) {
                 priv->server_id = make_server_id (gssdp_client_get_uda_version (client));
         }