devmapper: Maks createSnapDevice a function, not a method

No idea why this was a method. Maybe a cut and paste bug.

Docker-DCO-1.1-Signed-off-by: Alexander Larsson <alexl@redhat.com> (github: alexlarsson)
devmapper: Move error detection to devmapper.go

This moves the EBUSY detection to devmapper.go, and then returns
a real ErrBusy that deviceset uses.

Docker-DCO-1.1-Signed-off-by: Alexander Larsson <alexl@redhat.com> (github: alexlarsson)
devmapper: Simplify thin pool device id allocation

Instead of globally keeping track of the free device ids we just
start from 0 each run and handle EEXIST error and try the next one.

This way we don't need any global state for the device ids, which
means we can read device metadata lazily. This is important for
multi-process use of the backend.

Docker-DCO-1.1-Signed-off-by: Alexander Larsson <alexl@redhat.com> (github: alexlarsson)
devmapper: Store metadata in one file per device

This allows multiple instances of the backend in different containers
to access devices (although generally only one can modify/create them).

Any old metadata is converted on the first run.

Docker-DCO-1.1-Signed-off-by: Alexander Larsson <alexl@redhat.com> (github: alexlarsson)
reapply Cmd value even if CmdAdd returns early
Docker-DCO-1.1-Signed-off-by: Maximilian Goisser <goisser94@gmail.com> (github: hobofan)
UTIME_OMIT is only available on Linux

Docker-DCO-1.1-Signed-off-by: Kato Kazuyoshi <kato.kazuyoshi@gmail.com> (github: kzys)
Update hack/dind to mount cgroups on "/cgroup" instead of "/sys/fs/cgroup" for better compatibility

Fixes #5122

Docker-DCO-1.1-Signed-off-by: Andrew Page <admwiggin@gmail.com> (github: tianon)
modernise the MAINTAINER process documentation to line up with what I understand it to be

Docker-DCO-1.1-Signed-off-by: Sven Dowideit <SvenDowideit@fosiki.com> (github: SvenDowideit)
Adding Rohit Jnagal and Victor Marmol to pkg/cgroups maintainers.

Docker-DCO-1.1-Signed-off-by: Victor Marmol <vmarmol@google.com> (github: vmarmol)
Introduce x-axe scrolling to code-blocks.

This improvement introduces x-axe scrolling to code-blocks by
overriding certain default bootstrap word-wrapping constraints.

This PR closes: https://github.com/dotcloud/docker/issues/5279

Docker-DCO-1.1-Signed-off-by: O.S. Tezer <ostezer@gmail.com> (github: ostezer)
Add code for Pardot implementation to docs

Docker-DCO-1.1-Signed-off-by: O.S. Tezer <ostezer@gmail.com> (github: ostezer)
Update the run --net cli help to include the 'host' option

and then add that to the run and cli docs

Docker-DCO-1.1-Signed-off-by: Sven Dowideit <SvenDowideit@fosiki.com> (github: SvenDowideit)
Export cpuacct CPU usage in total cores over the sampled period.

Docker-DCO-1.1-Signed-off-by: Victor Marmol <vmarmol@google.com> (github: vmarmol)
registry: adding vbatts to the MAINTAINERS

Docker-DCO-1.1-Signed-off-by: Vincent Batts <vbatts@redhat.com> (github: vbatts)
Fix logo in README.md
Merge pull request #5631 from vmarmol/cpuacct-usage

Export cpuacct CPU usage in total cores over the sampled period.
Merge pull request #5622 from SvenDowideit/net-host-docs

Update the run --net cli help to include the 'host' option
use tabwriter to display usage in mflag

Docker-DCO-1.1-Signed-off-by: Victor Vieux <vieux@docker.com> (github: vieux)
improve some usages

Docker-DCO-1.1-Signed-off-by: Victor Vieux <vieux@docker.com> (github: vieux)
update the docs to reflect the nice \n handling

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