[gtk-vnc] connection: fix format string for auth failure

[Daniel P. Berrange <dberrange src gnome org>]

commit 3dfbc7c54abbad49c9a726bb66d7f78741263853
Author: Jakub Janků <jjanku redhat com>
Date:   Wed Mar 17 17:29:59 2021 +0100

    connection: fix format string for auth failure
    
    This error is visible when entering an empty password and results
    into an error message like this:
    
    "Unknown authentication failure: %s: Weak encryption key"
    
    Signed-off-by: Jakub Janků <jjanku redhat com>

 src/vncconnection.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/src/vncconnection.c b/src/vncconnection.c
index 5c55080..2426afd 100644
--- a/src/vncconnection.c
+++ b/src/vncconnection.c
@@ -3926,7 +3926,7 @@ static gboolean vnc_connection_perform_auth_vnc(VncConnection *conn)
     return vnc_connection_check_auth_result(conn);
 
 error:
-    vnc_connection_set_error(conn, "%s: %s", "Unknown authentication failure: %s",
+    vnc_connection_set_error(conn, "Unknown authentication failure: %s",
                              gcry_strerror(error));
     return FALSE;
 }