- Change the spotPrice default in the virtualizationSettings to 0
  instead of auto. Set to auto it was defaulting to doing bakes using
  spot, which is a big change from the way we have been operating.
- Need to quote the spot price in the templates, otherwise packer throws
  an error with "expected type 'string', got unconvertible type 'float64'"
- Leave the spotPriceAutoProduct set in the virtualization settings, so
  users can set just aws_spot_price in their bake stage and have it work
  as expected.