Do not open doors when actor has no path

When actor is not going anywhere it doesn't require to go through doors
so there is no need to open them.

apps/openmw/mwmechanics/aipackage.cpp

@@ -228,6 +228,9 @@ void MWMechanics::AiPackage::openDoors(const MWWorld::Ptr& actor)
     if (getTypeId() == TypeIdWander)
         return;
 
+    if (mPathFinder.getPathSize() == 0)
+        return;
+
     MWBase::World* world = MWBase::Environment::get().getWorld();
     static float distance = world->getMaxActivationDistance();