Add GetParentDeathSignal() to pkg/system

Docker-DCO-1.1-Signed-off-by: Bernerd Schaefer <bj.schaefer@gmail.com> (github: bernerdschaefer)
Update ubuntulinux.md

In Ubuntu 14.04, we should use

    $ sudo service docker.io restart

instead of

    $ sudo service docker restart
nsinit.Init() restores parent death signal before exec

Docker-DCO-1.1-Signed-off-by: Bernerd Schaefer <bj.schaefer@gmail.com> (github: bernerdschaefer)
nsinit.DefaultCreateCommand sets Pdeathsig to SIGKILL

Docker-DCO-1.1-Signed-off-by: Bernerd Schaefer <bj.schaefer@gmail.com> (github: bernerdschaefer)
integcli: resolve full path to docker binary

Setting dockerBinary to the full path of the Docker binary is a good
idea and this is now done in the test code.

Docker-DCO-1.1-Signed-off-by: Cristian Staretu <cristian.staretu@gmail.com> (github: unclejack)
add ValidateContextDirectory to utils/utils.go

This commit adds a function which can be used to ensure all contents of
a directory can be accessed.

This function doesn't follow symlinks to check if they're pointing to
files which exist. Such symlinks can be useful later.

Docker-DCO-1.1-Signed-off-by: Cristian Staretu <cristian.staretu@gmail.com> (github: unclejack)
use ValidateContextDirectory to validate context

This commit makes the Docker cli client use ValidateContextDirectory
before attempting to create a tarball out of the context. This ensures
we avoid errors such as "unexpected EOF" during the upload of the
context.

This check is done before uploading any data and can save time and
bandwidth for remote Docker daemons.

Docker-DCO-1.1-Signed-off-by: Cristian Staretu <cristian.staretu@gmail.com> (github: unclejack)
add test for issue #5270

Docker-DCO-1.1-Signed-off-by: Cristian Staretu <cristian.staretu@gmail.com> (github: unclejack)
Remove Trailing Whitespace in User-Agent

After removed, the User-Agent shows in log like this:

[debug] http.go:160 https://index.docker.io/v1/repositories/busybox/images --
HEADERS: map[User-Agent:[docker/0.11.1-dev go/go1.2.2 git-commit/8887e00-dirty kernel/3.14.3-n1 os/linux arch/amd64]]

The code also moved all validation work into validVersion,
to keep the main logic as clean.

Docker-DCO-1.1-Signed-off-by: Derek <crq@kernel.org> (github: crquan)
Make Cristian maintainer of integration-cli (he wrote it)

Docker-DCO-1.1-Signed-off-by: Solomon Hykes <solomon@docker.com> (github: shykes)
gocapability: upstream fix for unsporrted caps

@vmarmol has made the fix upstream for not failing if the capability
being dropped is returned as invalid from the syscall, which is the case
when the capability is not supported on the host.
This is a blocker presently for RHEL6.5 on CAP_SYSLOG. We have patched
around this in our RPM for the time being, but this is the proper fix.

See also https://github.com/dotcloud/docker/pull/5810

Docker-DCO-1.1-Signed-off-by: Vincent Batts <vbatts@redhat.com> (github: vbatts)
integcli: speed up TestBuildSixtySteps

This improves the TestBuildSixtySteps test by switching from busybox to
scratch and simply adding a file.

This lowers the execution time of that test from 20 seconds to 5
seconds.

Docker-DCO-1.1-Signed-off-by: Cristian Staretu <cristian.staretu@gmail.com> (github: unclejack)
Add readme file for the api directory

See issue #5873

Docker-DCO-1.1-Signed-off-by: Timothy <timothyhobbs@seznam.cz> (github: https://github.com/timthelion)
Add readme file for the archive directory

See issue #5873

Docker-DCO-1.1-Signed-off-by: Timothy <timothyhobbs@seznam.cz> (github: https://github.com/timthelion)
Add readme for daemon directory

See issue #5873

Docker-DCO-1.1-Signed-off-by: Timothy <timothyhobbs@seznam.cz> (github: https://github.com/timthelion)
Add readme for the daemonconfig directory

See Issue #5873

Docker-DCO-1.1-Signed-off-by: Timothy <timothyhobbs@seznam.cz> (github: https://github.com/timthelion)
Add README.md file for sysinit directory

Note, this text is just copied from sysinit.go

See Issue #5873

Docker-DCO-1.1-Signed-off-by: Timothy <timothyhobbs@seznam.cz> (github: https://github.com/timthelion)
Fixed description and keywords on Ubuntu installation docs

Docker-DCO-1.1-Signed-off-by: James Turnbull <james@lovedthanlost.net> (github: jamtur01)
command line nit
Merge pull request #5886 from financeCoding/mac_doc_nit

command line nit