introduced in
commit a0ebc6f898
Date: Sat Nov 9 08:47:48 2019 +0200
missing move operator=
Change-Id: I0607ad1afbcb1f2a86d1c7e0736e2549a5562b64
Reviewed-on: https://gerrit.libreoffice.org/82441
Tested-by: Jenkins
Reviewed-by: Noel Grandin <noel.grandin@collabora.co.uk>