Adds cn-north-1 to the list of AMIs for the NAT box for CloudFormation
Adds cn-north-1 to the list of AMIs for the NAT box for CloudFormation

[#105488550](https://www.pivotaltracker.com/story/show/105488550)

Signed-off-by: Thinh Nguyen <381db031081d050934f1b36fa4ab3bf1b5383408@emc.com>

cloudfoundry-incubator/bosh-aws-cpi-release,cloudfoundry-incubator/bosh-aws-cpi-release,cloudfoundry-incubator/bosh-aws-cpi-release