telepathy: Fix notification of is-favourite changes
telepathy: Fix notification of is-favourite changes

This ensures that the UI reflects errors in changing the is-favourite status
of a Tpf.Persona, rather than just blindly assuming they succeed.

renatofilho/folks2,renatofilho/folks2,pwithnall/folks,renatofilho/folks2,GNOME/folks,renatofilho/folks,pwithnall/folks,GNOME/folks,GNOME/folks,renatofilho/folks2,renatofilho/folks,pwithnall/folks,renatofilho/folks,renatofilho/folks