[Cleanup] Remove _previousTarget from bot.h (#3074)

# Notes
- This is unused.

zone/bot.cpp

@@ -2120,7 +2120,6 @@ bool Bot::Process()
 
 		_botOwner = 0;
 		_botOwnerCharacterID = 0;
-		_previousTarget = 0;
 
 		return false;
 	}
@@ -2398,11 +2397,9 @@ bool Bot::CanDoSpecialAttack(Mob *other) {
 	return true;
 }
 
-void Bot::SetTarget(Mob* mob) {
-	if(mob != this) {
-		if(mob != GetTarget())
-			_previousTarget = GetTarget();
-
+void Bot::SetTarget(Mob *mob)
+{
+	if (mob != this) {
 		NPC::SetTarget(mob);
 	}
 }
@@ -3917,7 +3914,6 @@ void Bot::Depop() {
 
 	_botOwner = 0;
 	_botOwnerCharacterID = 0;
-	_previousTarget = 0;
 	NPC::Depop(false);
 }
 

zone/bot.h

@@ -786,7 +786,6 @@ private:
 	EQ::InventoryProfile m_inv;
 	double _lastTotalPlayTime;
 	time_t _startTotalPlayTime;
-	Mob* _previousTarget;
 	uint32 _guildId;
 	uint8 _guildRank;
 	std::string _guildName;