./pkg/archive: clean up Stat_t assertion

inspired by @tonistiigi comment
(https://github.com/docker/docker/pull/8046/files#r19579960)

Signed-off-by: Vincent Batts <vbatts@redhat.com>
Fix typo in api docs: stdou -> stdout
Merge pull request #8863 from vbatts/vbatts-archive_stat

./pkg/archive: clean up Stat_t assertion
Remove `jsonData` argument from `image.StoreImage`

The argument specified the json data to save to disk when registering
a new image into the image graph. If it is nil, then the given image
is serialized to json and that is written by default. This default
behavior is sufficient if the given image was originally deserialzed
from this jsonData to begin with which has always been the case.

Signed-off-by: Josh Hawn <josh.hawn@docker.com> (github: jlhawn)
Merge pull request #8799 from jlhawn/remove_jsondata_arg

Remove `jsonData` argument from `image.StoreImage`
Merge pull request #8924 from pdericson/api-doc-fix

Fix typo in api docs: stdou -> stdout
Structured logging and --log-format daemon flag

Take advantage of logrus structured logging feature, and implement it on
core engines types to demonstrate a possible output.