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)
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>
Use dual-stack Dialer when talking to registy

Signed-off-by: Gleb M. Borisov <borisov.gleb@gmail.com>
Fix typo

Signed-off-by: Zach Borboa <zachborboa@gmail.com>
daemon: resolve the graphdriver to show

graphdriver is not always specified when the log printed, because
it's provided in another thread. This patch will fix this.

Signed-off-by: Qiang Huang <h.huangqiang@huawei.com>
Fix stdout premature EOF

Never close attached stream before both stdout and stderr have written
all their buffered contents. Remove stdinCloser because it is not needed
any more as the stream is closed anyway after attach has finished.

Fixes #3631

Signed-off-by: Andy Goldstein <agoldste@redhat.com>
Replace fast with quickly

Technically an adverb should be used there :-)
do not send hostconfig at start, as we do on create now

Signed-off-by: Victor Vieux <vieux@docker.com>
Add a link to some documentation about exec.

Docker-DCO-1.1-Signed-off-by: Sven Dowideit <SvenDowideit@docker.com> (github: SvenDowideit)
dockerimages.md: typo fix
Document alternate command to check encrypted TCP socket
as curl command seems to fail on OSX Mavericks

Signed-off-by: Nicolas De Loof <nicolas.deloof@gmail.com>
archive: tests and benchmarks for hardlinks

Adding moar information, so benchmark comparisons can be moar
comparative.

Signed-off-by: Vincent Batts <vbatts@redhat.com>
Tweaks to Dockerfile tutorial

Made a few tweaks to Dockerfile tutorial links and removed some cruft from the tutorial itself.

Docker-DCO-1.1-Signed-off-by: Fred Lifton <fred.lifton@docker.com> (github: fredlf)
Add back Best Practices link.

Docker-DCO-1.1-Signed-off-by: Fred Lifton <fred.lifton@docker.com> (github: fredlf)
registry/endpoint: make it testable

Signed-off-by: Vincent Batts <vbatts@redhat.com>
Vendor logrus logging framework

Signed-off-by: Alexandr Morozov <lk4d4@docker.com>
Use logrus everywhere for logging

Fixed #8761

Signed-off-by: Alexandr Morozov <lk4d4@docker.com>
Use common logging in engine

Signed-off-by: Alexandr Morozov <lk4d4@docker.com>
Remove pkg/log

Signed-off-by: Alexandr Morozov <lk4d4@docker.com>