manifest: Disable dconf editor
manifest: Disable dconf editor

It shows up as an app, which we don't want.  We need one of:

1) Add --enable-editor-only so this can be built as an app
2) Split it into a separate git repository

GNOME/gnome-ostree,chergert/gnome-continuous,vrutkovs/vrutkovs.github.io,chergert/gnome-continuous,GNOME/gnome-ostree,GNOME/gnome-ostree,chergert/gnome-continuous,djdeath/gnome-ostree,vrutkovs/vrutkovs.github.io,djdeath/gnome-ostree,djdeath/gnome-ostree,vrutkovs/vrutkovs.github.io