*Fix the bug that neutral creatures do not fight back.

--HG--
branch : trunk

src/game/Creature.cpp

@@ -1576,7 +1576,7 @@ bool Creature::canStartAttack(Unit const* who) const
         || !IsWithinDistInMap(who, GetAttackDistance(who)))
         return false;
 
-    if(!canAttack(who))
+    if(!canAttack(who, false))
         return false;
 
     return IsWithinLOSInMap(who);

src/game/Unit.cpp

@@ -8557,11 +8557,16 @@ bool Unit::isTargetableForAttack() const
     return isAttackableByAOE() && !hasUnitState(UNIT_STAT_DIED);
 }
 
-bool Unit::canAttack(Unit const* target) const
+bool Unit::canAttack(Unit const* target, bool force) const
 {
     assert(target);
 
-    if(!IsHostileTo(target))
+    if(force)
+    {
+        if(IsFriendlyTo(target))
+            return false;
+    }
+    else if(!IsHostileTo(target))
         return false;
 
     if(!target->isAttackableByAOE() || target->hasUnitState(UNIT_STAT_DIED))

src/game/Unit.h

@@ -928,7 +928,7 @@ class TRINITY_DLL_SPEC Unit : public WorldObject
 
         bool isTargetableForAttack() const;
         bool isAttackableByAOE() const;
-        bool canAttack(Unit const* target) const;
+        bool canAttack(Unit const* target, bool force = true) const;
         virtual bool IsInWater() const;
         virtual bool IsUnderWater() const;
         bool isInAccessiblePlaceFor(Creature const* c) const;