aws: Also set AWS_PROFILE for boto tool support

boto tools like s3cat don't respect AWS_DEFAULT_PROFILE. This
change sets the appropriate environment for both, assuming your
boto profiles are defined somewhere. You can build boto creds 
in ~/.aws/credentials by running something like:

cp ~/.aws/config ~/.aws/credentials
sed -i 's/profile //g' ~/.aws/credentials

On OSX, replace the sed command with:

sed -i '' 's/profile //g' ~/.aws/credentials