I've spent 1 hour today debugging why packer does not want to work with
ansible. It turns out `ansible-playbook` command was returning non-zero
exit status because of the file system permission problem.
Output before change:
% packer build rabbitmq.json
amazon-ebs output will be in this color.
1 error(s) occurred:
* exit status 1
Output after change:
amazon-ebs output will be in this color.
1 error(s) occurred:
* Error running "ansible-playbook --version": exit status 1
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