Make 'docker build' send non-err output to stdout

Right now 'docker build' will send:
   Sending build context to Docker daemon
to stderr, instead of stdout.  This PR fixes that.

I looked in the rest of api/client/commands.go for other cases
that might do this and only one jumped out at me:
  https://github.com/docker/docker/blob/master/api/client/commands.go#L2202
but I think if I changed that to go to stdout then it'll mess people up
who are expecting just the container ID to be printed to the screen and
there is no --quiet type of flag we can check.

Closes #9404

Signed-off-by: Doug Davis <dug@us.ibm.com>
add --cap-add=NET_ADMIN to make a new network device

inspired by #9452

Docker-DCO-1.1-Signed-off-by: Sven Dowideit <SvenDowideit@docker.com> (github: SvenDowideit)

Signed-off-by: Sven Dowideit <SvenDowideit@docker.com>
Add a fuse example, combining both SYS_ADMIN and --device

inspired by #9448 and #9487

Docker-DCO-1.1-Signed-off-by: Sven Dowideit <SvenDowideit@docker.com> (github: SvenDowideit)

Signed-off-by: Sven Dowideit <SvenDowideit@docker.com>
Return docker's root dir in docker -D info

This adds the docker daemon's root directory to docker info when running
in debug mode.  This allows the user to view the root directory where
docker is writing and storing state.

Signed-off-by: Michael Crosby <crosbymichael@gmail.com>
Fix chroot untar for zero padded archive from slow reader

Signed-off-by: Lewis Marshall <lewis@lmars.net>
docs: docker.service not services

Minor but important typo in the new systemd guide introduced in #9347.

Signed-off-by: Brandon Philips <brandon.philips@coreos.com>
docs: remove a trailing whitespace

Signed-off-by: Brandon Philips <brandon.philips@coreos.com>
docs: use systemd drop-ins instead of copying

Copying the entire docker service file isn't necessary to add an
environment variable, instead use a drop-in configuration file. The nice
side-effect is that the user gets any vendor updates to the
docker.service file.

Signed-off-by: Brandon Philips <brandon.philips@coreos.com>
Merge pull request #9489 from crosbymichael/info-root

Return docker's root dir in docker -D info
Merge pull request #9512 from duglin/Issue9404

Make 'docker build' send non-err output to stdout
Running a container that links to a container with --net host
should throw an error.

Docker-DCO-1.1-Signed-off-by: Jessica Frazelle <jess@docker.com> (github: jfrazelle)
Merge pull request #9567 from jfrazelle/8333-net-link-error

Throw error when container links to --net host container
Merge pull request #9539 from flynn/chroot-untar-empty-archive-slow

Fix chroot untar for zero padded archive from slow reader
Flush stdin from within chroot archive

This makes sure that we don't buffer in memory and that we also flush
stdin from diff as well as untar.

Signed-off-by: Michael Crosby <crosbymichael@gmail.com>
Merge pull request #9522 from SvenDowideit/add-some-cap-add-examples

Add some cap add examples
Merge pull request #9573 from crosbymichael/flush-stdin

Flush stdin from within chroot archive
Merge pull request #9559 from philips/use-dropins-in-systemd-article

docs: use systemd drop-ins instead of copying
Merge pull request #9558 from philips/fixup-typo-in-systemd-article

docs: docker.service not services