Use consistent ApplyLayer in overlayfs

Signed-off-by: Michael Crosby <crosbymichael@gmail.com>
Merge pull request #9510 from crosbymichael/chrootarchive

Use consistent ApplyLayer in overlayfs
Merge remote-tracking branch 'origin/master' into bump_v1.4.0

* origin/master: (509 commits)
  Use consistent ApplyLayer in overlayfs
  Something changed, broke the docs release script, and it seems that --exclude still doesn't work, so I'm removing it
  Fix output format where no variable specified in mount pkg
  Run 'go vet' on integration-cli.
  Remove unnessary abstraction deepEqual
  Remove unnecessary abstraction nLines
  cleanup: remove startCommand function, only used once, and unecessary abstraction.
  Be consistent about libtrust import path.
  Fix tests with old cmd function.
  Update the most recent released version of the docs as well.
  Talk about URL support and the real meaning of `-` in the latest `fromSrc` API documentation.
  Fix invalid argument error on push
  Remove the last references to overlayfs
  Rename the overlay storage driver
  Fix TarSum iteration test
  Webhooks documentation: second pass addressing @fredlf's comments
  Remove unused Engine.Logf
  Update dockerimages.md
  graphdb: initialize the database semi-idempotently on every connection.
  Rename overlayfs to overlay
  ...

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)