AWS stemcell build should not require specific envvars

[jmcarp]

The AWS stemcell build task requires environment variables specific to IAM user access and doesn't support alternative forms of AWS authentication, including instance profiles and STS tokens. Rather than expecting a specific authentication method, the AWS task should delegate authentication to the SDK. This may be as simple as replacing

    client = S3::Client.new(
      aws_access_key_id: aws_access_key_id,
      aws_secret_access_key: aws_secret_access_key,
      aws_region: aws_region
    )

with

    client = S3::Client.new

cc @wjwoodson

[cf-gitbot]

We have created an issue in Pivotal Tracker to manage this:

https://www.pivotaltracker.com/story/show/154181967

The labels on this github issue will be updated when the story is started.

[xtreme-sameer-vohra]

Thanks for reporting this @jmcarp, we'll take a look

[xtreme-sameer-vohra]

Hi @jmcarp,
You should be able to use instance profiles to authenticate now. Unfortunately, we had trouble getting STS tokens to work.

Thanks for the suggestion.
Sameer