EUCA-7336 - Fix for lack of security group name in landing page when new launchconfigs are created.

- Removed the 'lc_fetched'/'sg_fetched' checks. They were preventing a new LC from getting the group name set, because it didn't think the SG collection was loaded (it was). With the recent addition of the try/catch block in the populateGroupName function, it really doesn't care anyway. If it misses the SG the first time, the listener will fire it again and do it right.
- Made the collection change listeners more specific to stop the recursion of calling populateGroupName on a change, and setting group_name, triggering a change and calling populateGroupName...