Comment # 6 on bug 1179942 from Atri Bhattacharya

Seems to be a packagekit issue, since doing pkcon offline-trigger also gives
the same error:

> pkcon offline-trigger 
> Command failed:
> GDBus.Error:org.gtk.GDBus.UnmappedGError.Quark._pk_2dengine_2derror_2dquark.Code1: Prepared update not found: /var/lib/PackageKit/prepared-update