moom--pos-x returns unexpected value

[takaxp]

In some cases on w32, moom--pos-x returns unexpected value. Following cases are affected by the error.

• Move frame to the origin (0, 0) by moom-move-frame after fill-width, fill-bottom.
  • maximized
  • fill-screen
• moom-fill-top
• moom-fill-bottom
• Move frame to top edge by moom-move-to-edge-* after fill-width, fill-bottom.