Simplify fixed-time-of-day

Apparently time-of-day is sent to clients purely on
a fixed time interval, so the warning about extra
network traffic was incorrect.  We can just forcibly
set time of day each tick entirely server-side without
any ill effects on network clients.

mods/nc_player_sky/timeofday.lua

@@ -1,37 +1,8 @@
 -- LUALOCALS < ---------------------------------------------------------
-local math, minetest, nodecore, string
-    = math, minetest, nodecore, string
-local math_abs, string_format
-    = math.abs, string.format
+local minetest
+    = minetest
 -- LUALOCALS > ---------------------------------------------------------
 
-local fixedtime = 0.2
-
-local warncount = 0
-local nextwarn = 0
-local function warn(curtime)
-	warncount = warncount + 1
-	if nextwarn > 0 then return end
-	nodecore.log("warning", string_format(
-			"had to manually adjust time of day (e.g. %1.4f -> %1.4f)"
-			.. " %d time(s), which creates extra network traffic for all clients"
-			.. "; make sure time_speed = 0 (currently %d)",
-			curtime, fixedtime, warncount, minetest.settings:get("time_speed") or 72))
-	nextwarn = 300
-	warncount = 0
-end
-
-local timer = 0
-minetest.register_globalstep(function(dtime)
-		nextwarn = nextwarn - dtime
-		timer = timer - dtime
-		if timer > 0 then return end
-		timer = 4
-		local curtime = minetest.get_timeofday()
-		if math_abs(curtime - fixedtime) > 0.001 then
-			warn(curtime)
-			minetest.set_timeofday(fixedtime)
-		end
-	end)
+minetest.register_globalstep(function() minetest.set_timeofday(0.2) end)
 
 minetest.unregister_chatcommand("time")