Necrotic Aura will be present even for necromancers starting with no talents

git-svn-id: http://svn.net-core.org/repos/t-engine4@4741 51575b47-30f0-44d4-a5cc-537603b46e54

game/modules/tome/data/talents/spells/necrotic-minions.lua

@@ -24,6 +24,7 @@ newTalent{
 	mode = "sustained",
 	cooldown = 10,
 	sustain_mana = 10,
+	no_unlearn_last = true,
 	tactical = { BUFF = 2 },
 	die_speach = function(self, t)
 		if rng.percent(90) then return end