The strslice.StrSlice type is a string-slice with a custom JSON Unmarshal
function to provide backward-compatibility with older API requests (see
[moby@17d6f00] and [moby@ea4a067]).
Given that the type is assigned implicitly through the fields on HostConfig,
we can just use a regular []string instead.
[moby@17d6f00]: 17d6f00ec2
[moby@ea4a067]: ea4a06740b
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>