Improve sample session script

Include remote-ip-prefix in security group rules so they will appear with
Horizon bug https://bugs.launchpad.net/horizon/+bug/1165095
Add dns nameservers to subnet so they will be pushed by dhcp to instances.
Increase RAM on controller node

1024MB was too tight and node really slows when it starts using swap.
Remove the default libvirt Linux bridge virbr0

It is not needed and only complicates the various network command outputs
like iptables-save.
Adds some things to make working on nodes easier

Bash autocompetes and aliases.
Add user vagrant to groups quantum and nova.
Give group rw permissions on config files
Removed old folsom patch
Remove IP address from br-ex

Not sure why the folsom doc said to do so.
In a real deployment it would expose the network node at the ip level to
the external network and to the instances via their floating ips or the
snat gw.