add --releasever=/ to mkimage-yum.sh

I didn't realize the commit required a Docker-DCO so it failed the travis-ci build. So I removed the commit from my forked repo. Now it looks like there is a pull request with no commit. So here it is again:

Needed to add '--releasever=/' flag to run yum groupinstall on Centos7 (didn't try on anything else). This snippet from yum man page explains why:

```
Note: You may also want to use the option --releasever=/ when creating the installroot as otherwise the $releasever value is taken from the rpmdb within the installroot (and thus.  will  be  empty,  before  creation).
```

Docker-DCO-1.1-Signed-off-by: Matt Schurenko <matt.schurenko@gmail.com> (github: mschurenko)
devmapper: include dm_deps information in debug

Signed-off-by: Vincent Batts <vbatts@redhat.com>
daemon logging: unifying output and timestamps

A little refactor of the ./pkg/log so engine can have a logger instance

Signed-off-by: Vincent Batts <vbatts@redhat.com>
Adding self to various maintainers files.

Docker-DCO-1.1-Signed-off-by: Jessica Frazelle <jess@docker.com> (github: jfrazelle)
Implementing IPv6 functionality for ipallocator

Closes #6975

Signed-off-by: Malte Janduda <mail@janduda.net>
Add more names

Docker-DCO-1.1-Signed-off-by: Brian Goff <bgoff@cpuguy83-mbp.home> (github: cpuguy83)
Preserve extended attributes and acls on archlinux build

Failure to do this means that file capabilites are not preserved in the image.
Ping fails to work as a non-root user if cap_net_raw is capability is not set

Signed-off-by: Dan Griffin <dgriffin@peer1.com>
pkg/version: lint and add comments
docker save: Do not save to a terminal.

Docker-DCO-1.1-Signed-off-by: Erik Hollensbe <github@hollensbe.org> (github: erikh)
pkg/truncindex: lint and add comments

Docker-DCO-1.1-Signed-off-by: Cristian Staretu <cristian.staretu@gmail.com> (github: unclejack)
pkg/units: lint

Docker-DCO-1.1-Signed-off-by: Cristian Staretu <cristian.staretu@gmail.com> (github: unclejack)
pkg/timeutils: lint and add comments

Docker-DCO-1.1-Signed-off-by: Cristian Staretu <cristian.staretu@gmail.com> (github: unclejack)
registry: lint

Docker-DCO-1.1-Signed-off-by: Cristian Staretu <cristian.staretu@gmail.com> (github: unclejack)
pkg/graphdb: some linting

Docker-DCO-1.1-Signed-off-by: Cristian Staretu <cristian.staretu@gmail.com> (github: unclejack)
Container#AllocateNetwork: Simplify error handling.

The defer logic was a little tricky and was hiding one bug: `err` was
being redefined (with `:=`) and thus it escaped the defer error checking
logic.

Signed-off-by: Andrea Luzzardi <aluzzardi@gmail.com>
Add test for ignoring invalid dockerfile instructions

Signed-off-by: Tibor Vass <teabee89@gmail.com>
ignore invalid Dockerfile instructions and do not consider "docker-version" a Dockerfile instruction

Signed-off-by: Tibor Vass <teabee89@gmail.com>
back from camping, and making fred the docs 'guy in charge'

Docker-DCO-1.1-Signed-off-by: Sven Dowideit <SvenDowideit@docker.com> (github: SvenDowideit)
Increase the tag length limit from 30 to 128

Signed-off-by: Burke Libbey <burke.libbey@shopify.com>
Fix system socket/service unit files

Two problems how they are today:

In the current systemd unit files it is impossible to have the
docker.service started at system boot.  Instead enableing docker.service
will actually enable docker.socket.  This is a problem, as that means
any container with --restart=always will not launch on reboot.  And of
course as soon as you log in and type docker ps, docker.service will be
launched and now your images are running.  Talk about a PITA to debug!
The fix is to just install docker.service when people ask docker.service
to be enabled.  If an admin wants to enable docker.socket instead, that
is fine and will work just as it does today.

The second problem is a common docker devel workflow, although not
something normal admins would hit.  In this case consider a dev doing
the following:

systemctl stop docker.service

docker -d
[run commands]
[^C]

systemctl start docker.service

Running docker -d (without -F fd://) will clean up the
/var/run/docker.sock when it exits.  Remember, you just ran the docker
daemon not telling it about socket actviation, so cleaning up its socket
makes sense!  The new docker, started by systemd will expect socket
activation, but the last one cleaned up the docker.sock.  So things are
just broken.  You can, today, work around this by restarting
docker.socket.  This fixes it by telling docker.socket that it is
PartOf=docker.service.  So when docker.service is
started/stopped/restarted docker.socket will also be
started/stopped/restarted.  So the above semi-common devel workflow will
be fine.  When docker.service is stopped, so is docker.socket,   docker
-d (without -F fd://) will create and delete /var/run/docker.sock.
Starting docker.service again will restart docker.socket, which will
create the file an all is happy in the word.

Signed-off-by: Eric Paris <eparis@redhat.com>