This allows us to continue execution until a certain proportion of hosts
to fail. This can be useful at scale, where failures are common, and
restarting a deployment is time-consuming.
The default max failure percentage is 100, keeping the default
behaviour. A global max failure percentage may be set via
kolla_max_fail_percentage, and individual services may define a max
failure percentage via <service>_max_fail_percentage.
Note that all hosts in the inventory must be reachable for fact
gathering, even those not included in a --limit.
Closes-Bug: #1833737
Change-Id: I808474a75c0f0e8b539dc0421374b06cea44be4f
af6e1ca4fd