AWS Keys Not being Propagated to Instances via Userdata

The %ENV% string in contrib/python/src/py/hadoop/cloud/data/hadoop-ec2-init-remote.sh is mean to export various environment variables.

These variables exist in the invoking client shell process, but dont exist on the launched instance. In this specific case, the aws keys for S3/S3n access were being set to empty strings. Manually adding AWS ID/SECRET to the pairs dictionary passed to build_env_string in py.hadoop.cloud.service:209 fixes this problem, but introduces aws specific information to the Service class.

Should the ENV string do an assignment + export instead of just an export here?