This is required for a working CA root, as /etc/ssl/certs on a few
Linux distributions just contains a bunch of symlinks.
Container Linux and Debian have symlinks pointing to
/usr/share/ca-certificates, ArchLinux has symlinks pointing
to /etc/ca-certificates.
On Debian /etc/ssl/certs can also include symlinks pointing
to /usr/local/share/ca-certificates for local CA certificates.
Fix: kubeadm/#671
30d327e2b3