docker-gc ignores EXCLUDE_FROM_GC on Docker 1.10

[TamsynUlthara]

After upgrading to Docker 1.10, docker-gc ignored my EXCLUDE_FROM_GC setting and removed nearly all my local Docker images.

[mattnworb]

It sounds to me like Docker 1.10 changes the IDs of all of your images when migrating to the new storage format, so your excludes file will need to change it's contents.

[TamsynUlthara]

My excludes file only has labels, not IDs, e.g.:

debian:8
python:3\.5-alpine
rethinkdb:latest

[mattnworb]

Sorry to hear it caused an issue for you 😞 To be quite honest though at Spotify we are a few versions of Docker behind, and AFAIK Docker 1.10 is just freshly released, so I am not entirely surprised that there may be conflicts - which sound like the new storage engine could be at play.

[TamsynUlthara]

It wasn't a huge deal; I noticed it on my local dev machine, and it was nothing that couldn't be fixed by re-pulling and re-building. :-)

[zerthimon]

This PR fixes the issue: #93 for docker version >=1.10 deployments.
Works with docker pre 1.10