USN-6519-2: EC2 hibagent update

USN-6519-1 added IMDSv2 support to EC2 hibagent. This update provides the corresponding update for Ubuntu 16.04 LTS. Original advisory details: The EC2 hibagent package has been updated to add IMDSv2 support, as IMDSv1 uses an insecure protocol and is no longer recommended...