Fixed wrong use of Vector3 (which doesn't exist) instead of Vector on mathutils.

io_scene_niftools/modules/nif_import/armature/__init__.py

@@ -244,7 +244,7 @@ class Armature:
         b_bind = math.nif_bind_to_blender_bind(n_bind)
 
         # set the bone matrix - but set the tail first to prevent issues with zero-length bone
-        b_edit_bone.tail = mathutils.Vector3([0,0,1])
+        b_edit_bone.tail = mathutils.Vector([0,0,1])
         b_edit_bone.matrix = b_bind
         # link to parent
         if b_parent_bone: