Refactor and repair regular expression attempting to match present interfaces.
The refactored regular expression will match on enp* ens* eth* variants.
CoreOS vagrant's configuration code look for interface names starting with 'enp0', but in my case when deploying CoreOS image to libvirt environment interfaces had names 'ens4v1', 'ens5v2'
This patch should fix it, but it might be part of a bigger issue and having these two patterns might not cover all possible configurations.
Joshua Harshman
Kalman Hazins
Pavel Karoukin
Mitchell Hashimoto
Artur Roszczyk