Region is not correctly determined from the configuration file

[boxa99]

Setting the region in the configuration file is ineffective. I am attempting to use the instance role. I have determined that I am able to access the bucket using the instance role. The bucket is in us-east-1 and the ec2 instance is in ap-southeast-2. I am running version 2.2.0

# cat /etc/apt/s3auth.conf
Region = 'us-east-1'

# apt update
...
301  HTTP Error 301: Moved Permanently - Set s3auth.conf region to match bucket 'Region': bucket may not be in ap-southeast-2  [PermanentRedirect] The bucket you are attempting to access must be addressed using the specified endpoint. Please send all future requests to this endpoint.

It works correctly when using the environment:
AWS_REGION=us-east-1 apt update

[exodo-]

I did some debugging and it seems the region only gets set from the config file if there's also an AccessKey and Secret, which is incompatible with an instance role.

[cpitchford]

PR #74 works to fix this by changing when the Region value is pulled

1. From /etc/apt/s3auth.conf (even if AccessKey is not set in the file)
2. From $AWS_REGION
3. From ec2 meta-data service