Retain the ContactManager for the lifetime of the main window.
Retain the ContactManager for the lifetime of the main window.

The ContactManager doesn't cleanly disconnect its signals when it's finalized
(or initialized), so we need to retain it for the lifetime of the main window
to avoid segfaults. It's not worth fixing the ContactManager, since we're
planning to remove it.

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