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)
docker save: Do not save to a terminal.

Docker-DCO-1.1-Signed-off-by: Erik Hollensbe <github@hollensbe.org> (github: erikh)
install.sh: Fix for Amazon's Linux AMI

Use /etc/os-release to determine distro

Contents of /etc/os-release on Amazon Linux AMI 2014.09:
NAME="Amazon Linux AMI"
VERSION="2014.09"
ID="amzn"
ID_LIKE="rhel fedora"
VERSION_ID="2014.09"
PRETTY_NAME="Amazon Linux AMI 2014.09"
ANSI_COLOR="0;33"
CPE_NAME="cpe:/o:amazon:linux:2014.09:ga"
HOME_URL="http://aws.amazon.com/amazon-linux-ami/"

Signed-off-by: Amit Bakshi <ambakshi@gmail.com>
Signed-off-by: Jessica Frazelle <jess@docker.com>
check ID in os-release instead

Docker-DCO-1.1-Signed-off-by: Jessica Frazelle <jess@docker.com> (github: jfrazelle)
Rewrite ENTRYPOINT documentation covering all the combinations with examples.

Docker-DCO-1.1-Signed-off-by: Sven Dowideit <SvenDowideit@docker.com> (github: SvenDowideit)
save start error into State.Error

when a container failed to start, saves the error message into State.Error so
that it can be retrieved when calling `docker inspect` instead of having to
look at the log

Docker-DCO-1.1-Signed-off-by: Daniel, Dao Quang Minh <dqminh89@gmail.com> (github: dqminh)
Port number 49153(BeginPortRange) would be returned twice, causing duplication and potential errors.

If we first request port 49153 (BeginPortRange) explicitly, and later some time request the next free port (of same ip/proto) by calling RequestPort() with port number 0, we will again get 49153 returned, even if it's currently in use. Because findPort() blindly retured BeginPortRange the first run, without checking if it has already been taken.

Signed-off-by: shuai-z <zs.broccoli@gmail.com>
added test, gofmtd

Signed-off-by: shuai-z <zs.broccoli@gmail.com>
Gracefully handle network bridge without IP association at startup
Addresses #8444

Docker-DCO-1.1-Signed-off-by: Phil Estes <estesp@linux.vnet.ibm.com> (github: estesp)
Allowing resize tty to only work when container is started
Addresses #8728

Signed-off-by: Srini Brahmaroutu <srbrahma@us.ibm.com>
Use code generation to set IAMSTATIC instead of -X

Signed-off-by: Michael Hudson-Doyle <michael.hudson@linaro.org>
use code generation for GITCOMMIT/VERSION too

Signed-off-by: Michael Hudson-Doyle <michael.hudson@linaro.org>
finally, use code generation for INITSHA1 & INITPATH too

Signed-off-by: Michael Hudson-Doyle <michael.hudson@linaro.org>
Merge pull request #8453 from estesp/8444-create-bridge-error

Gracefully handle network bridge without IP association at startup
Merge pull request #8737 from brahmaroutu/resize_uponstart_8728

Allowing resize tty to only work when container is started
builder: some small fixups + fix a bug where empty entrypoints would not override inheritance.

Docker-DCO-1.1-Signed-off-by: Erik Hollensbe <github@hollensbe.org> (github: erikh)
Merge pull request #8671 from shuai-z/master

Port number 49153(BeginPortRange) would be returned twice, causing dupli...
Add --dryrun to allow testing to the docs-release site, and then fix the double dollar mistake

Docker-DCO-1.1-Signed-off-by: Sven Dowideit <SvenDowideit@docker.com> (github: SvenDowideit)
Merge pull request #8695 from SvenDowideit/add-details-to-entrypoint-docs

Rewrite ENTRYPOINT documentation covering all the combinations with exam...
Merge pull request #8722 from SvenDowideit/sven-cannot-bash

Add --dryrun to allow testing to the docs-release site, and then fix the...