Add AUDIT_WRITE cap

Fixes #6345

Thanks @larsks for outstanding investigation

Docker-DCO-1.1-Signed-off-by: Alexandr Morozov <lk4d4math@gmail.com> (github: LK4D4)
Fix incorrect path in ENTRYPOINT example

The ENTRYPOINT example uses "/usr/bin/ls" as path, but `ls` is located at `/bin/ls`.

Docker-DCO-1.1-Signed-off-by: Sebastiaan van Stijn <github@gone.nl> (github: thaJeztah)
Properly handle 0 being passed as a signal

Docker-DCO-1.1-Signed-off-by: Matt Heon <mheon@redhat.com> (github: mheon)
Merge pull request #7179 from LK4D4/add_cap_audit_write_#6345

Add AUDIT_WRITE cap
Merge pull request #7212 from mheon/kill_zero

Properly handle 0 being passed as a signal number
update go import path and libcontainer

Docker-DCO-1.1-Signed-off-by: Victor Vieux <vieux@docker.com> (github: vieux)
gofmt -s -w

Docker-DCO-1.1-Signed-off-by: Victor Vieux <vieux@docker.com> (github: vieux)
revert AUTHORS changes

Docker-DCO-1.1-Signed-off-by: Victor Vieux <vieux@docker.com> (github: vieux)
Merge pull request #7225 from vieux/update_path

update go import path and libcontainer
Merge pull request #7185 from thaJeztah/patch-1

Fix incorrect path in ENTRYPOINT example
Typo in dockervolumes.md line 141?
Merge pull request #7234 from michielbdejong/patch-1

Typo in dockervolumes.md line 141?
Rewrite check-config in Go and add it to docker info

Docker-DCO-1.1-Signed-off-by: Tibor Vass <teabee89@gmail.com> (github: tiborvass)
Add unit test for check-config

Docker-DCO-1.1-Signed-off-by: Tibor Vass <teabee89@gmail.com> (github: tiborvass)