Fix notify-osd script to listen for accessible-name/value signals only.
Fix notify-osd script to listen for accessible-name/value signals only.

Notify-osd has now been fixed to work properly with GTK 3.2+, and as a result,
it no longer emits a window create signal for notification bubbles, but that
really doesn't matter since accessible-name and accessible-value
signals are emitted when the data we care about has changed.

GNOME/orca,chrys87/orca-beep,GNOME/orca,pvagner/orca,chrys87/orca-beep,GNOME/orca,h4ck3rm1k3/orca-sonar,pvagner/orca,h4ck3rm1k3/orca-sonar,chrys87/orca-beep,h4ck3rm1k3/orca-sonar,GNOME/orca,chrys87/orca-beep,pvagner/orca,pvagner/orca