Add ec2-ami-tools v1.5.2
Merge with upstream v1.5.2
Bump changelog to v1.5.2-1
Add ec2-ami-tools v1.5.3
Fix handling of EC2_HOME env vars

Since v1.5.2 they now handle setting the EC2_AMI_HOME variable which
propagates to EC2_HOME, but this breaks finding the files in /etc, so
we need to strip off the EC2_HOME prefix from these files.
Bump debian version