patches/luci: drop firmware flash page

This removes link to flash Luci page from menu. The page is still
accessible but now user no longer has direct access to that page.

This is because we do not support updates or backups provided by that
page. Its behavior is potentially harmful and misses script for firmware
upgrade to work correctly. Removing it from menu is short patch that can
be applied for long time and should prevent users from tinkering with
something that is not intended to work on Turris.

patches/luci/hack/0001-Disable-flash-tab-because-Turris-is-autoupdated-and-.patch

+From 050f0ebfb65921f5a6f1ae9607c08ef8a25261d5 Mon Sep 17 00:00:00 2001
+From: =?UTF-8?q?Karel=20Ko=C4=8D=C3=AD?= <karel.koci@nic.cz>
+Date: Wed, 27 Nov 2019 13:53:07 +0100
+Subject: [PATCH] Disable flash tab because Turris is autoupdated and this is
+ not supported
+
+This only hides it just to make it less available. It still can be
+accessed by URL.
+---
+ modules/luci-mod-system/luasrc/controller/admin/system.lua | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/modules/luci-mod-system/luasrc/controller/admin/system.lua b/modules/luci-mod-system/luasrc/controller/admin/system.lua
+index 1e0bebb4f..9bebe7898 100644
+--- a/modules/luci-mod-system/luasrc/controller/admin/system.lua
++++ b/modules/luci-mod-system/luasrc/controller/admin/system.lua
+@@ -25,7 +25,7 @@ function index()
+ 	entry({"admin", "system", "leds"}, view("system/leds"), _("<abbr title=\"Light Emitting Diode\">LED</abbr> Configuration"), 60)
+ 		.file_depends = { "/sys/class/leds" }
+ 
+-	entry({"admin", "system", "flash"}, view("system/flash"), _("Backup / Flash Firmware"), 70)
++	-- entry({"admin", "system", "flash"}, view("system/flash"), _("Backup / Flash Firmware"), 70)
+ 
+ 	entry({"admin", "system", "reboot"}, view("system/reboot"), _("Reboot"), 90)
+ end
+-- 
+2.24.0
+