set the avatar to default FIRST when clearing avatar

apps/users.lua

@@ -151,10 +151,10 @@ app:post("user_clear_avatar", "/:username/clear_avatar", function(self)
     return {redirect_to = self:url_for("user", {username = self.params.username})}
   end
   local old_avatar_id = target_user.avatar_id
-  util.destroy_avatar(old_avatar_id)
   target_user:update({
     avatar_id = 1,
   })
+  util.destroy_avatar(old_avatar_id)
   util.inject_infobox(self, "Avatar cleared.")
   return {redirect_to = self:url_for("user_settings", {username = self.params.username})}
 end)