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)
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)
Check supplied hostname before using it.

Docker-DCO-1.1-Signed-off-by: Rohit Jnagal <jnagal@google.com> (github: rjnagal)
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)
pkg: networkfs: etchosts: fixed tests

This patch fixes the fact that the tests for pkg/networkfs/etchosts
couldn't build due to syntax errors.

Docker-DCO-1.1-Signed-off-by: Aleksa Sarai <cyphar@cyphar.com> (github: cyphar)
integration-cli: docker_cli_links: fixed broken tests

The tests weren't ... tested when last edited, this patch fixes
them so that they run and pass correctly.

Docker-DCO-1.1-Signed-off-by: Aleksa Sarai <cyphar@cyphar.com> (github: cyphar)
Remove support for MemoryReservation in systemd systems. This has been
deperecated since systemd 208.

Docker-DCO-1.1-Signed-off-by: Victor Marmol <vmarmol@google.com> (github: vmarmol)
Merge pull request #5626 from cyphar/networkfs-etchosts-tests

Fixed broken tests for pkg/networkfs/etchosts
Merge pull request #5627 from cyphar/integration-cli-fixes

Fixed completely broken integration-cli tests
Merge pull request #5629 from vmarmol/fix-systemd-softlimit

Remove support for MemoryReservation in systemd systems.
Merge pull request #5630 from rjnagal/libcontainer-fixes

Check supplied hostname before using it.
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)
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)