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>
Prettify docs-update.py

Remove commented code, use format for string concatenation, split long lines, fix how-to-run instructions
Signed-off-by: Davide Ceretti <dav.ceretti@gmail.com>
Add ENV variables support to WORKDIR build command

Docker-DCO-1.1-Signed-off-by: Cristian Staretu <cristian.staretu@gmail.com> (github: unclejack)
Docker-DCO-1.1-Signed-off-by: Adrien Folie <folie.adrien@gmail.com> (github: folieadrien)

Conflicts:
	builder/builder.go
		This file has been deleted.
add test and move one from rm to rmi

Signed-off-by: Victor Vieux <vieux@docker.com>
Add more names

Docker-DCO-1.1-Signed-off-by: Brian Goff <bgoff@cpuguy83-mbp.home> (github: cpuguy83)
Multiple fixes to the cli.md document.

*. Fixed headings so the side menu will now be consistent. Some sections
had H3s that were displaying and others did not leaving the left menu
very mismatched.

* Fixed several spelling errors.

* Re-formatted several long lines and badly laid out paragraphs.

* Fixed several double backticks.

* Added backticks to several outputs and variables.

* Removed two issues that are no longer valid.

* Removed several double spaces and extra lines.

Docker-DCO-1.1-Signed-off-by: James Turnbull <james@lovedthanlost.net> (github: jamtur01)
Remove registry v2 code path

As this feature requires more testing it is much safter to get the
underlying changes into the codebase first then enable the feature in
another release after proper testing and verification can be done.

Signed-off-by: Michael Crosby <crosbymichael@gmail.com>
Fix builder/parser so it keeps some whitespace on split lines.
If previous line ends with whitespace, or next line starts with whitepsace
we need to preserve a space otherwise things line:
RUN echo\
   hello
will appear as: RUN echohello

Noticed this while looking at #5744 because he had lines ending in &&\

Signed-off-by: Doug Davis <dug@us.ibm.com>
Make fixed font sizes smaller per Issue #5278

Closes #5278

Signed-off-by: Doug Davis <dug@us.ibm.com>
Fix Host header on stream commands

Fixes #8407

Setting Host on URL only works if the Request does not
already have its Host property set.

Note that the API version was also swallowed.

Signed-off-by: Tõnis Tiigi <tonistiigi@gmail.com> (github: tonistiigi)
pkg/version: lint and add comments
Fix streaming JSON Content-type for postBuild

See #8101

lineDelim is used by streamJSON() so it needs to be set
before its called.

Signed-off-by: Tõnis Tiigi <tonistiigi@gmail.com> (github: tonistiigi)
Merge pull request #8413 from tonistiigi/build-content-type

Fix streaming JSON Content-type for postBuild
Merge pull request #8408 from tonistiigi/8407-fix-host-header

Fix Host header on stream commands
docker save: Do not save to a terminal.

Docker-DCO-1.1-Signed-off-by: Erik Hollensbe <github@hollensbe.org> (github: erikh)
Fix TestBuildCacheADD to check cache in out, not in id

Signed-off-by: Alexandr Morozov <lk4d4@docker.com>
Merge pull request #8343 from duglin/Issue5278

Make fixed font sizes smaller per Issue #5278
Merge pull request #8391 from crosbymichael/disable-v2-registry

Remove registry v2 code path