Adapt flatpak build to upstream changes
<https://github.com/flathub/org.libreoffice.LibreOffice/commit/
4bed50e14d9d106093b027bc8bb780023fb42b55>
"gvfs: Update gvfs-1.54.1.tar.xz to 1.54.2 (#295)"
<https://github.com/flathub/org.libreoffice.LibreOffice/commit/
88a0d0718a9ddcd75a0842b5173e6d6ecd4d3bde>
"--enable-ext-nlpsolver (#297)"
Change-Id: Ie39c22c2611a31a8e2a82ae200b7a3836393dff3
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/170177
Tested-by: Jenkins
Reviewed-by: Stephan Bergmann <stephan.bergmann@allotropia.de>
(cherry picked from commit
6b80e0554e4b11f9c1eb955c2d26445bc6855371)
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/170121