Don't set NODE_IP_ADDRESS and -PORT in the env file

We already set them via tcp_listeners in the main configuration file. The
config file allow specifying multiple listeners which we will need for allowing
trove to access rabbitmq. But those setting are overridden if NODE_IP_ADDRESS
and/or NODE_PORT are present in the env file.
Allow to specifying multiple tcp_listener addresses
Add support for rabbitmq to listen on the public network

This is a requirement of Trove. The trove-guest-agent, running inside an
instance, needs access to a rabbitmq instance to be able receive messages from
trove-api. As instances don't have access to the "admin" network we need to be
able to open up the rabbitmq configuration to additionally listen on the public
interface.
Allow to create trove configuration

This includes crating a vhost, a user and permissions for that user to the
vhost.
Clarify comment on set_permissions call
Cleanup when trove features are disabled
Merge pull request #53 from rhafer/trove

trove related enhancements
Nitpicking: add empty line for readability
Merge pull request #58 from vuntz/nitpick

Nitpicking: add empty line for readability