When running Ansible in check mode (aka dry run), some tasks need some
changes, specially around variables and make sure they are actually
defined.
Note: the backport is not clean, and we also fixed the tasks when paunch
is enabled, which wasn't the case anymore in the initial patch on
master. Also the tasks which check healthcheck aren't needed in check
mdoe, they take too much time for nothing.
Change-Id: I337aa287f1c88a0e2707b441fc6b19b997d52385
(cherry picked from commit a199da6a08)
(cherry picked from commit ebbad0d542)
ab3548f23a