mdev configs for linking NVMe devs --> EBS devs
This allows things (i.e. CloudStor & REX-Ray docker plugins) that expect /dev/sdX and /dev/xvdX devices on the instance to work with NVMe devices on newer instance types.
Also, a recent packer change (some time before 1.3.3) necessitates the setting of the build region, if packer is run outside of AWS.
Also-also, bumping release to be in sync with the recently released alpine 3.8.2.