This fixes a few bugs in the container store related to reading and
writing fields. Specifically, on update, the full field set wasn't being
returned to the caller, making it appear that the store was corrupted.
We now return the correctly updated field and store the missing field
that was omitted in the original implementation. In course, we also have
defined the update semantics of each field, as well as whether or not
they are required.
The big addition here is really the container metadata testsuite. It
covers listing, filtering, creates, updates and deletes in a vareity of
scenarios.
Signed-off-by: Stephen J Day <stephen.day@docker.com>
783ed05057