see <https://github.com/flathub/org.libreoffice.LibreOffice/issues/57>
"OpenJDK 11 is available".

Change-Id: Ie24ed7349ca9a4a57c1a8d18d10b29c4a37e259c
Reviewed-on: https://gerrit.libreoffice.org/65830
Tested-by: Jenkins
Reviewed-by: Stephan Bergmann <sbergman@redhat.com>