From http://www.freedesktop.org/wiki/Software/systemd/PredictableNetworkInterfaceNames/
You disable the assignment of fixed names, so that the unpredictable
kernel names are used again. For this, simply mask udev's rule file for
the default policy: ln -s /dev/null
/etc/udev/rules.d/80-net-setup-link.rules (since v209: this file was
called 80-net-name-slot.rules in release v197 through v208)
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