fix(vagrant): enable patch-docker

This oneshot job needs to be run on every reboot.
fix(contrib/vagrant): prevent Vagrant reboots

Turns out, we were stopping the update-manager service but not the
update-engine-reboot-manager service.

fixes #753
chore(contrib/vagrant): update CoreOS box image

Ideally the CoreOS team will start publishing their
.box images to vagrantcloud.com, but until they do,
to bake the fresh version we'll need to point to a
specific CoreOS release.

fixes #755
refactor(client): fix program flow of --no-remote

If you specified --no-remote, "git remote deis added" would still
be displayed. This moves that logic into the try/catch block so it
will only be printed if it hits there.
Merge pull request #754 from opdemand/stop_vagrant_reboots

fix(contrib/vagrant): prevent Vagrant reboots
Merge pull request #757 from opdemand/hotfix-no-remote

refactor(client): fix program flow of --no-remote
Merge pull request #750 from opdemand/enable-patched-docker

fix(vagrant): enable patch-docker
Merge pull request #756 from opdemand/update_virtualbox_image

chore(contrib/vagrant): update CoreOS box image
docs(concepts): add back build/release/run docs

closes #740