general: Kill off NAUTILUS_WINDOW_OPEN_FLAG_CLOSE_BEHIND
bb884cb6 changed the accelerator for open-file-and-close-window from alt-shift-down to ctrl-shift-down, which now conflicts with keyboard rubberbanding in the canvas view. Additionally, it’s nothing more than a relict from a more spatial time.
https://bugzilla.gnome.org/show_bug.cgi?id=765526
Fixes #701 (closed)