Add more specific lvm2 version to PACKAGERS document

I personally tested this using our container, and this was the lowest version that compiles and runs properly.

Docker-DCO-1.0-Signed-off-by: Andrew Page <admwiggin@gmail.com> (github: tianon)
Update docker_remote_api_v1.8.rst

Docker-DCO-1.1-Signed-off-by: Jean-Baptiste Dalido <jbdalido@gmail.com> (github: jeandalido)
Update docker_remote_api_v1.7.rst and non-versionned

Docker-DCO-1.1-Signed-off-by: Jean-Baptiste Dalido <jbdalido@gmail.com> (github: jeandalido)
Inline the test.docker.io fingerprint in the install.sh script as well

As long as we're doing it, we ought to do it for all the "official" Docker properties at least

Docker-DCO-1.1-Signed-off-by: Andrew Page <admwiggin@gmail.com> (github: tianon)
Add ca-certificates to our package Recommends

It's only in "Recommends" because it's only required for all but the esoteric configurations (since you can't "docker pull" from the index without it, but that's about it).

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

Docker-DCO-1.0-Signed-off-by: Victor Vieux <victor.vieux@docker.com> (github: vieux)
Merge pull request #3490 from vieux/image_export_job

Move image_export to a job
Use '-s empty' instead of '-s dir'

This *should* have the same effect as the previous strategy: Instead of
'mkdir empty; fpm -s dir -C empty ...' we can simply do 'fpm -s empty'

Docker-DCO-1.1-Signed-off-by: Jordan Sissel <jls@semicomplete.com> (github: jordansissel)
Merge pull request #3555 from jordansissel/patch-1

Update Ubuntu packaging script to use 'fpm -s empty' instead of 'mkdir empty && fpm -s dir -C empty'
Merge pull request #3500 from tianon/lvm2-version

Add more specific lvm2 version to PACKAGERS document
Merge pull request #3539 from jeandalido/patch-1

Update docker_remote_api_v1.8.rst
Merge pull request #3551 from tianon/test-docker-io-gpg-fingerprint

Inline the test.docker.io fingerprint in the install.sh script as well
Merge pull request #3554 from tianon/ubuntu-dep

Add ca-certificates to our package Recommends