Fix warnings concerning deprecated use of bare variables

[pchaigno]

Using bare variable in with_items results in the following with the last version of Ansible (2.0.2.0-1):

[DEPRECATION WARNING]: Using bare variables is deprecated. Update your playbooks
 so that the environment value uses the full variable syntax ('{{some_var}}').
This feature will be removed in a future release. Deprecation warnings can be
disabled by setting deprecation_warnings=False in ansible.cfg.

[coveralls]

Coverage decreased (-0.09%) to 87.252% when pulling 5999b0c on warning-variables into 3838a44 on master.

[awailly]

I kind of preferred the with_items: on several lines, but if this is how they changed the format, good to merge!

[pchaigno]

I put all with_items on a single line for consistency, both across with_items statements and with regard to other single-value statements.