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>
The "testing" package adds some flags in its init function, so utilities
that import distribution code may print a page of extra testing flags in
their help output.
This commit solves the issue by moving an import of "testing" in the
registry/storage/cache package to a new
registry/storage/cache/cachecheck package, which is only imported by
tests.
Signed-off-by: Aaron Lehmann <aaron.lehmann@docker.com>