This change allows the user to specify `-backend-config="encrypt=1"`
to tell S3 to encrypt the data that's in the bucket when using S3
for remote config storage.
The encryption uses "Amazon S3-managed encryption keys" so it should
not require any further user intervention.
A line was added to the unit test just for coverage.
The acceptance test was modified to:
a) Use encryption
b) Push some test data up to the bucket created to ensure
that Amazon accepts the header.
This landed in aws-sdk-go yesterday, breaking the AWS provider in many places:
3c259c9586
Here, with much sedding, grepping, and manual massaging, we attempt to
catch Terraform up to the new `awserr.Error` interface world.
Radek Simko