Unnecessary double dialog-info NOTIFY in 1.9.x

[dsandras]

This seems wrong to me. I had backported it to 1.8, and all it does is triggering a second NOTIFY each time a call is hangup, generating twice the NOTIFY load for each watcher on call end.

See:
d3602cf#commitcomment-3718000

Reporting it here so that nobody forgets about it.