This will be used during export tests, to ensure libreoffice
extensions are properly added to the schema.

Change-Id: Ia24d914fbe67c135fd8e3ed1add8dbf8fbc05a72
Reviewed-on: https://gerrit.libreoffice.org/28449Reviewed-by: Thorsten Behrens <Thorsten.Behrens@CIB.de>
Tested-by: Thorsten Behrens <Thorsten.Behrens@CIB.de>