Fix for bgo#585418 - Orca duplicated says the slider values
Fix for bgo#585418 - Orca duplicated says the slider values

This was a result of the speech generator refactor -- an old
bug (bgo#340559) crept back in.

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