Added fredlf's suggested changes.

Signed-off-by: Hollie Teal <hollie@docker.com>
Removed merge conflict artifacts.

Signed-off-by: Hollie Teal <hollie@docker.com>
Updated CentOS documentation to reflect CentOS 7 install.
Added reference to CentOS Dockerfiles on github.

Signed-off-by: Jim Perrin <jperrin@centos.org> (github: jperrin)
Update docker-attach.1.md
Fix race condition in sending started signal from monitor

Signed-off-by: Alexandr Morozov <lk4d4math@gmail.com>
Fix race between container cleanup and inspect/ps

Signed-off-by: Alexandr Morozov <lk4d4math@gmail.com>
Fix race on state serialization

Signed-off-by: Alexandr Morozov <lk4d4math@gmail.com>
Cleanup: Make channels unbuffered

Signed-off-by: Alexandr Morozov <lk4d4math@gmail.com>
Merge pull request #7582 from LK4D4/fix_races

Fix some race conditions
Merge pull request #7546 from hollietealok/master

Added fredlf's suggested changes.
Merge pull request #7562 from jperrin/master

Updated CentOS documentation to reflect CentOS 7 install.
Merge pull request #7581 from samuel-phan/patch-1

Update docker-attach.1.md
daemon: build: allow the USER directive to modify the owner of COPY'd files

This patch ensures that the USER directive will change the owner of any
COPY'd files or directories to the user id and primary group id of the
user which the builder's run config currently runs as. The user and
primary groups ids are ascertained using the same process and package as
libcontainer to ensure consistency (the same defaults are also used).

Signed-off-by: Aleksa Sarai <cyphar@cyphar.com> (github: cyphar)
integration-cli: add tests for USER changing owner of COPY'd files

This patch adds integration-cli tests for a wide variety of USER
directives to ensure that they all act consistently with the RUN
directive in terms of the owner of COPY'd files.

Signed-off-by: Aleksa Sarai <cyphar@cyphar.com> (github: cyphar)