Add code for Pardot implementation to docs

Docker-DCO-1.1-Signed-off-by: O.S. Tezer <ostezer@gmail.com> (github: ostezer)
fix(daemon): ensure the /var/lib/docker dir exists

The btrfs driver attempts to stat the /var/lib/docker directory to
ensure it exists. If it doesn't exist then it bails with an unhelpful
log line:

```
2014/05/10 00:51:30 no such file or directory
```

In 0.10 the directory was created but quickly digging through the logs I
can't tell what sort of re-ordering of code caused this regression.

Docker-DCO-1.1-Signed-off-by: Brandon Philips <brandon.philips@coreos.com> (github: philips)
Dockerfile: updated ubuntu release used for builds

This patch just revs the Ubuntu release used for builds from 13.10
to 14.04.

Docker-DCO-1.1-Signed-off-by: Aleksa Sarai <cyphar@cyphar.com> (github: cyphar)
Fix bug on LXC container start. Fixes #5718
Docker-DCO-1.1-Signed-off-by: Fernando Mayo <fernando@tutum.co> (github: fermayo)
Remove signal_freebsd (already in pkg/signal)

Docker-DCO-1.1-Signed-off-by: Guillaume J. Charmes <guillaume@charmes.net> (github: creack)
Integration test for link and unlink containers

Docker-DCO-1.1-Signed-off-by: Fabio Falci <fabiofalci@gmail.com> (github: fabiofalci)
Give the Redirect a HostName - filled in from the s3 bucket name.

Docker-DCO-1.1-Signed-off-by: Sven Dowideit <SvenDowideit@fosiki.com> (github: SvenDowideit)
reduce cache time to 1 hours so future docs releases update the cloudfront caches faster

Docker-DCO-1.1-Signed-off-by: Sven Dowideit <SvenDowideit@fosiki.com> (github: SvenDowideit)
libcontainer: Create dirs/files as needed for bind mounts

If you specify a bind mount in a place that doesn't have a file yet we
create that (and parent directories). This is needed because otherwise
you can't use volumes like e.g. /dev/log, as that gets covered by the
/dev tmpfs mounts.

Docker-DCO-1.1-Signed-off-by: Alexander Larsson <alexl@redhat.com> (github: alexlarsson)
Merge pull request #5730 from SvenDowideit/fix-hostname-for-redirects

Give the Redirect a HostName - filled in from the s3 bucket name.
Merge pull request #5731 from SvenDowideit/reduce-cache-max-age

reduce cache time to 1 hours so future docs releases update the cloudfront caches faster
Merge pull request #5621 from ostezer/docs-add-pardot

Add code for Pardot implementation to docs
Merge pull request #5741 from creack/remove_unused_file-2

Remove signal_freebsd (already in pkg/signal)
Merge pull request #5729 from fabiofalci/link_unlink_test

Integration test for link and unlink containers
runmetrics update, linking to collectd plugin rather than just hinting
Correct a comment in libcontainer Mount Namespace setup.
Docker-DCO-1.1-Signed-off-by: Vishnu Kannan <vishnuk@google.com> (github: vishh)
Merge pull request #5712 from vishh/fix_typo

Correct a libcontainer Mount Namespace setup comment.
Merge pull request #5724 from tutumcloud/5718-lxcbugfix

Fix bug on LXC container start. Fixes #5718
Remove newline char in error message
Docker-DCO-1.1-Signed-off-by: Michael Crosby <michael@crosbymichael.com> (github: crosbymichael)
Merge pull request #5748 from crosbymichael/libcontainer-bindmounts

libcontainer: Create dirs/files as needed for bind mounts