[gnome-commander] Null check

[Uwe Scholz <uwescholz src gnome org>]

commit 7f4ef39cbed76ec05dd20c806b5d6d0c13b939ce
Author: Uwe Scholz <u scholz83 gmx de>
Date:   Wed Nov 10 22:49:14 2021 +0100

    Null check

 src/gnome-cmd-con.cc | 2 ++
 1 file changed, 2 insertions(+)
---
diff --git a/src/gnome-cmd-con.cc b/src/gnome-cmd-con.cc
index ce02416d..427e27fe 100644
--- a/src/gnome-cmd-con.cc
+++ b/src/gnome-cmd-con.cc
@@ -455,6 +455,8 @@ void gnome_cmd_con_add_bookmark (GnomeCmdCon *con, gchar *name, gchar *path)
 
 void gnome_cmd_con_erase_bookmark (GnomeCmdCon *con)
 {
+    g_return_if_fail (GNOME_CMD_IS_CON (con));
+
     GnomeCmdBookmarkGroup *group = con->priv->bookmarks;
     for(GList *l = group->bookmarks; l; l = l->next)
     {