Add an attribute to InstanceGroup and AutoScalingGroup to return the ips

This is so you can make a custom loadbalancer that can reference the
group's instance ip's.

fixes bug #1131025
Change-Id: I32d76d3627704ad503e2ec06bf0da39cf79f33d2
Merge "Add an attribute to InstanceGroup and AutoScalingGroup to return the ips"