Fix broken filtering for images used by containers

[chekunkov]

Fixes errors like this:

Error calling remove_image image=xxx:latest 409 Client Error: Conflict ("conflict: unable to remove repository reference "xxx:latest" (must force) - container 91ab644a7b31 is using its referenced image 7caea3c78386")

The error is caused by mismatch between entry in image_tags_in_use and tag produced inside filter_images_in_use

For in my local tests image used by container without tags and with id 'sha256:ff5f2ec93a207bdf948f986bc94e938977979befedd53121a32e8d74fc58fb8e' produced set set(['sha256:ff5f2:latest']) that didn't match with entry from the image_tags_in_use which was full image id.

Also see #14

[chekunkov]

Tests fail because of pypa/setuptools#951, probably should be fixed in another PR

[dnephin]

Thanks, I think this is a good change, but we need to get CI fixed before we can merge.

Are you familiar with the issue? Is the fix just to require a specific version of setuptools in requirements.txt ?

[chekunkov]

Hi @dnephin Yes, pinning setuptools to a specific version should fix the issue, e.g. that's what we've done in scrapinghub/scrapinghub-stack-hworker#17

[dnephin]

I clicked rebuild on travis, it seems things are fixed.

[dnephin]

LGTM

[dnephin]

cc @danielhoherd @solarkennedy

[solarkennedy]

Thanks!