src/contrib/ec2/bin/hadoop-ec2-env-sh on 0.18.0 still has values for the 0.17.x branch. Here is a diff. I used this to create an EC2 image, which works for my hadoop streaming project. The java version is the latest one, as instructed by the docs, but I left the java URL blank, as it looks like it isn't persistent.
ChimpBook4:bin karl$ diff hadoop-ec2-env.sh- hadoop-ec2-env.sh-foo