chore(contrib/*): update to CoreOS 324.1.0

Double-check the IDs:
EC2: https://coreos.com/docs/running-coreos/cloud-providers/ec2/
Rackspace: https://coreos.com/docs/running-coreos/cloud-providers/rackspace/
fix(Makefile): update to work with fleetctl 0.3.2
fix(data-containers): change test command to "inspect"

We used "docker start" to test for the existence of data containers,
but this can fail after the container has run, and cause the || clause
also to fail with "name in use".
fix(controller): use new `fleetctl` semantics

Fleetctl 0.3.2 by default will test for a unit's goal status 10 times,
once every tenth of a second, before failing. This is not generous
enough, so on starting services we do it async with `-no-block` and
then poll for goal status, and on stopping we wait 60 seconds.
fix(controller): watch fifth column for state

fleetctl v0.3.4 introduced a fifth column, so we need to update
the location of the state column.
docs(contrib/rackspace): document manual update for CoreOS

Since the Rackspace images are updated infrequently, we still use
CoreOS 317.0.0 images on Rackspace. This commit details the workaround
to manually update CoreOS to the latest release from the channel.
Merge pull request #1019 from deis/coreos-317.0.0

chore(contrib/*): update CoreOS to 324.1.0
fix(Makefile): enable targets to work for non-Vagrant

Adds DEIS_HOSTS, which is set automatically or can be overridden
for non-Vagrant platforms. This is used by ssh_all to determine
which hosts to SSH into - previously, we used `vagrant ssh`,
which obviously only works on Vagrant.

This also updates all the Makefiles to use fleet as appropriate,
and to pull / build / etc. on all DEIS_HOSTS.

TESTING: try the various make commands on Vagrant and Rackspace/EC2

replaces #998
closes #811
Merge pull request #1026 from deis/deis_hosts

fix(Makefile): enable targets to work for non-Vagrant
fix(travis): add dummy FLEETCTL_TUNNEL envvar

This fixes the errors we are seeing on TravisCI.

replaces #1045
Merge pull request #1048 from deis/fix-travis

fix(travis): add dummy FLEETCTL_TUNNEL envvar
docs(UPGRADING.md): add upgrade documentation

Adds documentation outlining two upgrade workflows for Deis clusters.

closes #1012