Do not fall back to us-east-1 when fetching the current instance
Do not fall back to us-east-1 when fetching the current instance

Previously, if the region was not specified, then calling current_instance()
on an EC2 host would fail if it was not in us-east-1. Instead, calculate
the region if we don't explicitly specify it when asking for
current_instance().

artfinder/awslib