Changes name of ansible module kolla_docker to
kolla_container.

Change-Id: I13c676ed0378aa721a21a1300f6054658ad12bc7
Signed-off-by: Martin Hiner <m.hiner@partner.samsung.com>

We sometimes have the requirement that images should explicitly not
be pulled. Using the service-images-pull tag, it is now possible to
skip the actual pull task by using --skip-tags.

Change-Id: Ia00a5ecbcb944c252cd9d0366d8cf1e7ff6327f7

Sometimes, the registries may intermittently fail to deliver the
images. This is often seen in the CI, though it also happens with
production deployments, even those with internal registries and/or
registry mirrors - due to sheer load when trying to pull the
images from many hosts.

This patchs adds two new vars to control retry behaviour.
The default has been set to make users happier by default. :-)

Change-Id: I81ad7d8642654f8474f11084c6934aab40243d35

We get a nice optimisation by using a filtered loop instead
of task skipping per service with 'when'.

Partially-Implements: blueprint performance-improvements
Change-Id: I8f68100870ab90cb2d6b68a66a4c97df9ea4ff52