Commit 54f8fc4090 introduced the use of
wl_surface::set_buffer_scale, which is only available starting with
version 3 of the wl_compositor protocol. Because we already prefer
version 4 when available, this went unnoticed but broke versions 1, 2
and 3 when reaching the wl_surface::set_buffer_scale call.
This restores functionality for version 3 and properly document that
versions 1 and 2 are not supported anymore.
Signed-off-by: Nicolas Guichard <nicolas.guichard@kdab.com>
(cherry picked from commit bcc0587ab9)
Part-of: <https://gitlab.freedesktop.org/xorg/xserver/-/merge_requests/2076>