Fix permissions on ADD/COPY

Fix a regression introduced in PR#9467 when a single file was added or
copied.

Signed-off-by: Arnaud Porterie <arnaud.porterie@docker.com>
Merge pull request #9597 from icecrime/9467-chown_regression

Fix permissions on ADD/COPY
add note to docs about overlay + btrfs

Docker-DCO-1.1-Signed-off-by: Jessica Frazelle <jess@docker.com> (github: jfrazelle)
Merge pull request #9566 from jfrazelle/btrfs-overlayfs

add note to docs about overlay + btrfs unsupported
Merge remote-tracking branch 'origin/master' into bump_v1.4.0

* origin/master: (554 commits)
  add note to docs about overlay + btrfs
  Fix permissions on ADD/COPY
  Fix interactive TLS postContainersAttach
  Use Set for stderr "logs" job in builder
  Forbid client piping to tty enabled container
  Add test for exec tty stdin close
  User should get error message on wrong config closes #9501
  Added description for 'docker run' command, -c/--cpu-shares flag
  Flush stdin from within chroot archive
  Running a container that links to a container with --net host should throw an error.
  docs: use systemd drop-ins instead of copying
  docs: remove a trailing whitespace
  docs: docker.service not services
  Removed race condition If two interrupts were fired really quickly interruptCount could have been incremented twice before the LoadUint32 making cleanup not being called at all.
  Fix chroot untar for zero padded archive from slow reader
  LXC CAP ADD CAP DROP IN TEMPLATE
  Return docker's root dir in docker -D info
  I was talking to someone whom i listen to, and she noted that our docs don't mention the license
  Add a fuse example, combining both SYS_ADMIN and --device
  add --cap-add=NET_ADMIN to make a new network device
  ...

Docker-DCO-1.1-Signed-off-by: Jessica Frazelle <jess@docker.com> (github: jfrazelle)
Bump version to v1.4.0

Docker-DCO-1.1-Signed-off-by: Jessica Frazelle <jess@docker.com> (github: jfrazelle)