Fix the documentation regarding usage by root / sudoer

[Eran Rom]

The docs suggest if you are not using ROOT you can drive the ansible script using (ansible-playbook -s -i storlet.yml), generally speaking this will not work because sudo prompts for a password, so what the docs should say is to use the combination of -s -K, the later prompts for a password.
    With that said, the above is going to cause problems, namely due to the following invocation (here's just one example) python /opt/ibm/add_new_tenant.py service swift
    The ansible script calls a python program that starts a process which drives another anible script, but of course if you weren't using root (and -K) it'll attempt to prompt, implying it will simply hang forever waiting for input.
    Given this I think we need to specify that the user used for SSH is either root, or has sudo with passwordless SSH (e.g. rsa between all the hosts).