bump(coreos-base/coreos-init): Updates for empty /etc

Fix some issues for booting without using tmpfiles to setup the root
filesystem in advance. For example this now works reliably:

    mkdir -p c/etc
    cp /etc/os-release c/etc
    ln -s usr/lib64 c/lib
    ln -s usr/lib64 c/lib64
    ln -s usr/bin c/bin
    ln -s usr/sbin c/sbin
    systemd-nspawn --directory=c --bind=/usr --boot
Merge pull request #685 from marineam/init

bump(coreos-base/coreos-init): Updates for empty /etc