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>
Add more names

Docker-DCO-1.1-Signed-off-by: Brian Goff <bgoff@cpuguy83-mbp.home> (github: cpuguy83)
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>
Add some docs about which env vars are defined in new containers

@SvenDowideit FYI

Closes #3087

Signed-off-by: Doug Davis <dug@us.ibm.com>
Minor changes to SSHd example

Docker-DCO-1.1-Signed-off-by: James Turnbull <james@lovedthanlost.net> (github: jamtur01)
docs: fixing docker.io api

Signed-off-by: Lajos Papp <lajos.papp@sequenceiq.com>
Fix href in docs w.r.t. cgroups freezer pointer

Apparently, the [...] and (http...) need to be right after each other instead
of on different lines.

Signed-off-by: Doug Davis <dug@us.ibm.com>
Fix typo: reguardless should be regardless

Signed-off-by: Doug Davis <dug@us.ibm.com>
Add more info about the LINK env vars created

@SvenDowideit see what you think. I'd like to get your take on this
before I submit the PR.

Closes #4789

Signed-off-by: Doug Davis <dug@us.ibm.com>
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>
start sending robots.txt (and humans.txt) again, and set to dissallow if its not the real docs site

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