BKR-1586 - allow an 'as-is' container to be used rather than rebuilding every time

[oldNoakes]

As per https://tickets.puppetlabs.com/browse/BKR-1586 this change allows a new flag to be defined for the docker hypervisor use_image_as_is which will cause the provision step of the process to simply pull the image down and use it without rebuilding it.

This pushes the responsibility for setting up a root:root ssh process on the container onto the user but has the benefit of speeding up test time by only having to do a docker pull rather than a docker build

[puppetlabs-jenkins]

Can one of the admins verify this patch?

[smcelmurry]

test this please

[oldNoakes]

Hey @smcelmurry - did you need further tests for this (is merged though) - didn't add a functional test as all the containers I could find that had the root:root password pre-built were generally user builds rather than any official builds and didn't seem like a good idea to add as a test - can publish a container with this setup if needed.

Thanks.

[oldNoakes]

Also thanks :) - this is speeding up our build times by about 70%