gtk-2-24 has new strings

[Federico Mena Quintero <federico ximian com>]

Dear translators,

I've just pushed some changes to the file chooser in the gtk+ module,
specifically to the gtk-2-24 branch.  Although right now the focus is
3.x, we will likely have another release in the 2.24.x series for GTK+.
Please update your translations there :)

(The idea is to have the file chooser as similar as possible between
2.24.x and 3.x, so that even apps which still require GTK+ 2 will get
all the goodness - and users will get consistent behavior.)

Thanks!

  Federico