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>
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>
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