[orca-list] caja: selection of icons doesn't announce with orca

[kendell clark <coffeekingms gmail com>]

hi all
Steps to reproduce. Open up the caja file manager, which is the
filemanager for  the mate desktop. Make sure you're in icon mode by
pressing alt+v to enter the view menu and selecting icons. Try to select
icons by pressing shift plus the arrow keys. Orca should announce the
icons as being selected, but instead it's silent. Tested with both orca
stable, 3.18.2 and current orca master. Note that this is the gtk2
version. In the gtk3 version, the icon view doesn't speak at all yet.
Thanks
Kendell Clark