Setting config to release parameters.
Get public IP from minion-computed grains.

It was of course absurd to try and send the IP as a creation option from
the master, since the IP is not known until after the fallback proxy is
launched.
salt-cloud 0.8.8 was broken; getting it from github.

salt-cloud 0.8.8 was crashing when trying to deploy a map file with
multiple machines, only some of which were present.  github HEAD
(as of this writing) doesn't have that problem, so while we don't
get a salt-cloud release that works I'm just installing from that
particular commit.