user-controls: Add a fallback bus connection
This is a hack to allow MctUserControls
to be used from GtkBuilder
templates, where it’s not possible to pass construct-only properties in
to the MctUserControls
constructor. It’s not feasible to make
MctUserControls:dbus-connection
not construct-only, because it gets
used to construct an MctManager
which then subscribes to various
signals.
So for the cases where MctUserControls
is used from a builder
template, the code has to connect to the system bus manually, which is
possibly (though unlikely) a blocking operation.
This fixes a critical warning when enabling parental controls in gnome-initial-setup.
Signed-off-by: Philip Withnall withnall@endlessm.com