Set SriovNetSupport to "simple". As of February 2017, this applies to C3, C4,
D2, I2, R3, and M4 (excluding m4.16xlarge).
Set EnaSupport to true. As of February 2017, this applies to C5, I3, P2, R4,
X1, and m4.16xlarge.
This commit adds a new type of builder which builds an AMI based on a
snapshot of an EBS volume which is provisioned on a "surrogate"
instance. This can be used to build operating system images from
scratch, but unlike the `chroot` builder does not require running from
an AWS EC2 instance.