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)
Fix the bug of tag a existed tag name of a repository.

Signed-off-by: Lei Jitang <leijitang@huawei.com>
Minor changes to SSHd example

Docker-DCO-1.1-Signed-off-by: James Turnbull <james@lovedthanlost.net> (github: jamtur01)
client: even cleaner use of Transport

First off, sorry for the noise. This is a cleaner step of #8508

Found more of a root cause of the open file handles.
After more testing I found that the open file descriptors will still
occur for TCP:// connections to the daemon, causing client and/or daemon
to fail.

The issue was instantiating a new http.Transport on _ever_ client
request. So each instance held the prior connection alive, but was only
ever used once.

By moving it out to the initilization of DockerCli, we can now have
reuse of idled connections. Simplifies the garbage overhead of the
client too, though that's not usually a deal.

Signed-off-by: Vincent Batts <vbatts@redhat.com>
Add info on --device flag permissions ':rwm'

Signed-off-by: Sven Dowideit <SvenDowideit@home.org.au>

Docker-DCO-1.1-Signed-off-by: Sven Dowideit <SvenDowideit@home.org.au> (github: SvenDowideit)
Link directly to the 'latest' release alias

Docker-DCO-1.1-Signed-off-by: Sven Dowideit <SvenDowideit@docker.com> (github: SvenDowideit)
Move registry search API docs into the registry API document.

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