GLib API change for 3.2

[David Zeuthen <zeuthen gmail com>]

Hey,

In https://bugzilla.gnome.org/show_bug.cgi?id=659699 a problem with
gdbus-codegen(1) was discovered and we decided to break API to fix it.

This means that code using the new D-Bus ObjectManager interfaces and
gdbus-codegen(1) will have to be rebuilt. In GNOME, this includes
nautilus and gnome-online-accounts. As neither of these projects
distributes generated code, only a rebuild is needed, no need for new
tarballs or anything.

Thanks,
David