Undoing the Finish Pixels tool doesn't restore the position correctly.

[Cameron White]

With latest development build of Pinta on Ubuntu 12.10:

Steps to reproduce:
1) Create a new image, and draw some stuff with the paintbrush.
2). Ctrl+A to select everything, and switch to the Move Pixels tool.
3) Drag to move the selected contents somewhere, and then switch to another tool to add Finish Pixels to the history.
4) After pressing Ctrl+Z to undo, the selection moves back to its original position, even though the Move Pixels action hasn't been undone yet.

[Cameron White (cameronwhite91)]

Fixed: https://github.com/PintaProject/Pinta/commit/af3cee1b2f3abc9e5ca5e2b43b34751f5a0a5dce