luci-base: dispatcher: remove tree modifier support

This feature was never used, is hardly documented and appears to be
designed to fiddle with the internal dispatch tree state.

Given that, simply drop the related code to simplify the dispatcher
class somewhat.

Signed-off-by: Jo-Philipp Wich <jo@mein.io>

modules/luci-base/luasrc/dispatcher.lua

@@ -595,11 +595,9 @@ function createtree()
 
 	local ctx  = context
 	local tree = {nodes={}, inreq=true}
-	local modi = {}
 
 	ctx.treecache = setmetatable({}, {__mode="v"})
 	ctx.tree = tree
-	ctx.modifiers = modi
 
 	local scope = setmetatable({}, {__index = luci.dispatcher})
 
@@ -609,28 +607,9 @@ function createtree()
 		v()
 	end
 
-	local function modisort(a,b)
-		return modi[a].order < modi[b].order
-	end
-
-	for _, v in util.spairs(modi, modisort) do
-		scope._NAME = v.module
-		setfenv(v.func, scope)
-		v.func()
-	end
-
 	return tree
 end
 
-function modifier(func, order)
-	context.modifiers[#context.modifiers+1] = {
-		func = func,
-		order = order or 0,
-		module
-			= getfenv(2)._NAME
-	}
-end
-
 function assign(path, clone, title, order)
 	local obj  = node(unpack(path))
 	obj.nodes  = nil

modules/luci-base/luasrc/dispatcher.luadoc

@@ -81,15 +81,6 @@ Build the index before if it does not exist yet.
 @name createtree
 ]]
 
----[[
-Register a tree modifier.
-
-@class function
-@name modifier
-@param	func	Modifier function
-@param	order	Modifier order value (optional)
-]]
-
 ---[[
 Clone a node of the dispatching tree to another position.