pass address of metaHeaders to GetenvJson in ImagePush and ImagePull

Docker-DCO-1.1-Signed-off-by: kies <lleelm@gmail.com> (github: kieslee)
Add ability to pause/unpause containers via cgroups freeze

This patch adds pause/unpause to the command line, api, and drivers
for use on containers.  This is implemented using the cgroups/freeze
utility in libcontainer and lxc freeze/unfreeze.

Co-Authored-By: Eric Windisch <ewindisch@docker.com>
Co-Authored-By: Chris Alfonso <calfonso@redhat.com>
Docker-DCO-1.1-Signed-off-by: Ian Main <imain@redhat.com> (github: imain)
Integrating systemd freeze functionality.

This pulls together #6061 and #6125

Docker-DCO-1.1-Signed-off-by: Chris Alfonso <calfonso@redhat.com> (github: calfonso)
Add stats for memory allocation failure count and instantaneous cpu usage in the usermode and kernelmode.

Docker-DCO-1.1-Signed-off-by: Vishnu Kannan <vishnuk@google.com> (github: vishh)
Merge pull request #6195 from kieslee/master

pass address of metaHeaders to GetenvJson in ImagePush and ImagePull
Merge pull request #6198 from vishh/stats2

Add more stats to libcontainer.
Merge pull request #6178 from calfonso/freezer-pr-integration

Freezer integration to support container pause/unpause