* etc/schema/od-schema-v1.2-os.rnc: Delete.
* etc/schema/OpenDocument-schema-v1.3.rnc:
* etc/schema/OpenDocument-schema-v1.3+libreoffice.rnc:
Copy from Emacs tree.
* etc/schema/schemas.xml: Incorporate changes from Emacs's f1f351def.
This is not a typical port because Org's schemas.xml is a subset of
Emacs's. The changes here follow what's proposed in
<https://orgmode.org/list/87o8d07mpr.fsf@kyleam.com>, with the
addition of copying OpenDocument-schema-v1.3+libreoffice.rnc (which I
overlooked when writing that message).
Kyle Meyer