registry: make certain headers optional

For a pull-only, static registry, there only a couple of headers that
need to be optional (that are presently required.
* X-Docker-Registry-Version
* X-Docker-Size
* X-Docker-Endpoints

Docker-DCO-1.1-Signed-off-by: Vincent Batts <vbatts@redhat.com> (github: vbatts)
registry: Info collection

roll version and standalone information into the _ping. And to support
Headers they are checked after the JSON is loaded (if there is anything
to load). To stay backwards compatible, if the _ping contents are not
able to unmarshal to RegistryInfo, do not stop, but continue with the
same behavior.

Docker-DCO-1.1-Signed-off-by: Vincent Batts <vbatts@redhat.com> (github: vbatts)
docker daemon: show info about the server

For combing through logs, have an intro line with information about the
running instance of the docker daemon.

Docker-DCO-1.1-Signed-off-by: Vincent Batts <vbatts@redhat.com> (github: vbatts)
Add new validate-dco and validate-gofmt bundlescripts for DCO and gofmt validation

Docker-DCO-1.1-Signed-off-by: Andrew Page <admwiggin@gmail.com> (github: tianon)
Remove the old Travis-specific files that are no longer necessary

Docker-DCO-1.1-Signed-off-by: Andrew Page <admwiggin@gmail.com> (github: tianon)
Engine: optional Logging field to disable custom logging in engine.

* The default behavior is preserved
* This disables the use of the `TEST` environment variable in engine.

Docker-DCO-1.1-Signed-off-by: Solomon Hykes <solomon@docker.com> (github: shykes)
Add contrib/man to our generated deb

Docker-DCO-1.1-Signed-off-by: Andrew Page <admwiggin@gmail.com> (github: tianon)
Fix a few minor man formatting consistency issues

Some flags ended with a colon, some didn't.  For man pages, the prevailing normal practice is not to end the flags lines with colons.

Docker-DCO-1.1-Signed-off-by: Andrew Page <admwiggin@gmail.com> (github: tianon)
Update check-config.sh with more kernel configs and more reliable cgroup hierarchy/subsystem check

Docker-DCO-1.1-Signed-off-by: Andrew Page <admwiggin@gmail.com> (github: tianon)
Added reactive-docker to list of remote API clients

Docker-DCO-1.1-Signed-off-by: H. Rapp <webmaster@3kolor.com> (github: almoehi)
docker save: fix filemode permissions

currently the files created are not readable. This makes the files and
directories permissions more sane.

Docker-DCO-1.1-Signed-off-by: Vincent Batts <vbatts@redhat.com> (github: vbatts)
Merge pull request #5079 from unclejack/bump_v0.10.0

Bump version to v0.10.0
Change version to v0.10.0

Docker-DCO-1.1-Signed-off-by: Cristian Staretu <cristian.staretu@gmail.com> (github: unclejack)
Merge pull request #5101 from unclejack/merge_release_v0.10.0

Merge release v0.10.0
Make remote API unit tests easier to read and write

Docker-DCO-1.1-Signed-off-by: Solomon Hykes <solomon@docker.com> (github: shykes)
Merge pull request #5022 from tianon/make-validate

Add "make validate" for both local and CI gofmt and DCO verification
Update dns and volumes-from docs
Docker-DCO-1.1-Signed-off-by: Michael Crosby <michael@crosbymichael.com> (github: crosbymichael)
Check for apparmor enabled on host to populate profile
Docker-DCO-1.1-Signed-off-by: Michael Crosby <michael@crosbymichael.com> (github: crosbymichael)
Change shm mode to 1777

Fixes #5126
Docker-DCO-1.1-Signed-off-by: Michael Crosby <michael@crosbymichael.com> (github: crosbymichael)
Revert "Support hairpin NAT without going through docker server"

This reverts commit b39d02b611f1cc0af283f417b73bf0d36f26277a.

Docker-DCO-1.1-Signed-off-by: Michael Crosby <michael@crosbymichael.com> (github: crosbymichael)