contact-chooser: add 'activate' signal
contact-chooser: add 'activate' signal

https://bugzilla.gnome.org/show_bug.cgi?id=661993

GNOME/telepathy-account-widgets,Distrotech/telepathy-account-widgets,GNOME/telepathy-account-widgets,Distrotech/telepathy-account-widgets,GNOME/telepathy-account-widgets