[gnome-latex] Revert "LaTeX commands: Avoid superfluous and fatal cast to Gtk.Activatable"

[Sébastien Wilmet <swilmet src gnome org>]

commit f24c864519e6e7108a4b56574278c67b79f6679d
Author: Sébastien Wilmet <swilmet gnome org>
Date:   Wed Jul 25 12:45:45 2018 +0200

    Revert "LaTeX commands: Avoid superfluous and fatal cast to Gtk.Activatable"
    
    This reverts commit 02f35b9dc60eab0cf741e44740e12c91daf9ea8e.
    
    I've discovered more crashes when gnome-latex is compiled with valac git
    master (what will become vala 0.42). I don't plan to work on gnome-latex
    anytime soon, so in the meantime gnome-latex will need to be compiled
    with vala 0.40. With this revert the nice thing is that gnome-latex
    cannot be compiled with vala git master, but can be compiled with vala
    0.40.

 src/latex_menu.vala | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/src/latex_menu.vala b/src/latex_menu.vala
index 4480dc8..f965d23 100644
--- a/src/latex_menu.vala
+++ b/src/latex_menu.vala
@@ -500,7 +500,7 @@ public class LatexMenu : Gtk.ActionGroup
     private Gtk.Action get_menu_tool_action (string name, string? label, string? icon_name)
     {
         Gtk.Action action = new MenuToolAction (name, label, label, icon_name);
-        MenuToolButton menu_tool_button = new MenuToolButton (null, null);
+        Activatable menu_tool_button = (Activatable) new MenuToolButton (null, null);
         menu_tool_button.set_related_action (action);
         return action;
     }