Simplify the manager objects.

Part of RR-112. It didn't make any sense to see 8 IP addresses in
the manager list when you first start reactor. It's pointless to
have all the public IPs there, so we just pick one and allow the
user to provide it as a command-line argument.

Change-Id: I61f7be2e77062b555f42a2c67720412fa7a7e9b7
Ensure Reactor URL is available in guests.

THis is part of RR-112. To effectively use Reactor from within
the instances, it's important to have the URL available. This is
done differently depending on the cloud type, but the API will be
available via the variable REACTOR_API in both cases.

Change-Id: If91ab9f3d13d6d32659c206ed747ab7ae8913dea
Merge "Ensure Reactor URL is available in guests."