Make sure err never gets masked

Defining err as named return parameter will make sure the variable gets
assigned before returning and thus avoid masking

Docker-DCO-1.1-Signed-off-by: Johannes 'fish' Ziemke <github@freigeist.org> (github: discordianfish)
Clean up the docker socket on termination of the daemon.

Docker-DCO-1.1-Signed-off-by: Erik Hollensbe <github@hollensbe.org> (github: erikh)
fix docker integration-cli restart test race

Docker-DCO-1.1-Signed-off-by: Erik Hollensbe <github@hollensbe.org> (github: erikh)
Add Go 1.2 to Travis so we make sure we keep retrocompat for a little while

Docker-DCO-1.1-Signed-off-by: Andrew Page <admwiggin@gmail.com> (github: tianon)
Merge pull request #7311 from tianon/travis-old-go

Add Go 1.2 to Travis so we make sure we keep retrocompat for a little while
Move parsing functions to pkg/parsers and the specific kernel handling
functions to pkg/parsers/kernel, and parsing filters to
pkg/parsers/filter. Adjust imports and package references.

Docker-DCO-1.1-Signed-off-by: Erik Hollensbe <github@hollensbe.org> (github: erikh)
Merge pull request #7286 from erikh/parsers

Move parsing functions to parsers/ and the specific kernel handling...
Add OS to docker info

Docker-DCO-1.1-Signed-off-by: Tibor Vass <teabee89@gmail.com> (github: tiborvass)
Merge pull request #7215 from tiborvass/add-os-to-docker-info

Add OS to docker info
Merge pull request #6962 from erikh/3349-cleanup-docker-socket

Clean up the docker socket on termination of the daemon.
Remove CheckSum from utils; replace with a TeeReader

Docker-DCO-1.1-Signed-off-by: Erik Hollensbe <github@hollensbe.org> (github: erikh)
Partition server/ by image, init, events, container, and "everything left"

Docker-DCO-1.1-Signed-off-by: Erik Hollensbe <github@hollensbe.org> (github: erikh)
Merge pull request #7331 from erikh/simplify_checksum

Simplify utils.CheckSum.Read to use TeeReader instead
Merge pull request #7317 from erikh/server_split

Partition server/ by image, init, events, container, and "everything left"
Merge pull request #7298 from erikh/fix_cli_restart_test

fix docker integration-cli restart test race
Merge pull request #7100 from discordianfish/fix-port-allocation

Fix masked err in portmapper
Bump libcontainer dep

Docker-DCO-1.1-Signed-off-by: Andrew Page <admwiggin@gmail.com> (github: tianon)
Add support for autodetected HOME from USER (if HOME is unset)

Docker-DCO-1.1-Signed-off-by: Andrew Page <admwiggin@gmail.com> (github: tianon)
Remove pkg/user now that it's embedded in libcontainer

Docker-DCO-1.1-Signed-off-by: Andrew Page <admwiggin@gmail.com> (github: tianon)