Since Go 1.7, context is a standard package. Since Go 1.9, everything
that is provided by "x/net/context" is a couple of type aliases to
types in "context".
Many vendored packages still use x/net/context, so vendor entry remains
for now.
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
This fix adds `--filter enabled=true` to `docker plugin ls`,
as was specified in 28624.
The related API and docs has been updated.
An integration test has been added.
This fix fixes 28624.
Signed-off-by: Yong Tang <yong.tang.github@outlook.com>
