Back in the before time, the best practices surrounding usage of Context
weren't quite worked out. We defined our own type to make usage easier.
As this packaged was used elsewhere, it make it more and more
challenging to integrate with the forked `Context` type. Now that it is
available in the standard library, we can just use that one directly.
To make usage more consistent, we now use `dcontext` when referring to
the distribution context package.
Signed-off-by: Stephen J Day <stephen.day@docker.com>
By adding WithVersion to the context package, we can simplify context setup in
the application. This avoids some odd bugs where instantiation order can lead
to missing instance.id or version from log messages.
Signed-off-by: Stephen J Day <stephen.day@docker.com>
