Since our Docker image moved to Ubuntu, we mistakenly copy
dist/docker/etc/sysconfig/scylla-server to /etc/sysconfig, which is not
used in Ubuntu (it should be /etc/default).
So /etc/default/scylla-server is just default configuration of
scylla-server .deb package, --log-to-stdout is 0, same as normal installation.
We don't want keep the duplicated configuration file anyway,
so let's drop dist/docker/etc/sysconfig/scylla-server and configure
/etc/default/scylla-server in build_docker.sh.
Fixes#10270Closes#10280
(cherry picked from commit bdefea7c82)
69a1325884