[NetworkManager-openconnect] Don't allow empty useragent string to be used for override

[David Woodhouse <dwmw2 src gnome org>]

commit 9a8533af5b3078126a51b2ac17e1df2834f7fdb6
Author: David Woodhouse <dwmw2 infradead org>
Date:   Sat Apr 30 20:35:10 2022 +0100

    Don't allow empty useragent string to be used for override

 auth-dialog/main.c | 4 ++++
 1 file changed, 4 insertions(+)
---
diff --git a/auth-dialog/main.c b/auth-dialog/main.c
index 8aca03f..6a3b164 100644
--- a/auth-dialog/main.c
+++ b/auth-dialog/main.c
@@ -1884,6 +1884,10 @@ static auth_ui_data *init_ui_data (char *vpn_name, GHashTable *options, GHashTab
        g_unix_set_fd_nonblocking(ui_data->cancel_pipes[0], TRUE, NULL);
        g_unix_set_fd_nonblocking(ui_data->cancel_pipes[1], TRUE, NULL);
 
+       /* If it's an empty string, forget it. */
+       if (vpn_useragent && !*vpn_useragent)
+               vpn_useragent = NULL;
+
        ui_data->vpninfo = (void *)openconnect_vpninfo_new(vpn_useragent ?: "OpenConnect VPN Agent 
(NetworkManager)",
                                                           validate_peer_cert, write_new_config,
                                                           nm_process_auth_form, write_progress,