AWS CPI no longer mutates AWS class varables
AWS CPI no longer mutates AWS class varables

Instead of setting the keys and region as global state then using the
EC2 client we can just pass those values to the client instance and
leave the global state alone.

[#89044786]
Signed-off-by: Jonathan Barnes <bc7add126c2dbb8382bf1c28ac262b9363a32706@pivotal.io>

barthy1/bosh,barthy1/bosh,barthy1/bosh,barthy1/bosh