docs(contrib/rackspace): Rackspace details

Added Rackspace Load Balancer details.
docs(*): add load balancer info to EC2 and Rackspace
Merge pull request #1485 from deis/add_load_balancer_instructions

docs(*): add load balancer info to EC2 and Rackspace
chore(*): bump CoreOS to 386.1.0

Includes internal fixes, notably some bigger ones for systemd 215.
Merge pull request #1487 from deis/coreos_386.1.0

chore(*): bump CoreOS to 386.1.0