Gui 1162 UX review for adding VPC support on the instance launch and launch config wizards

https://eucalyptus.atlassian.net/browse/GUI-1162
https://eucalyptus.atlassian.net/browse/GUI-1228
https://eucalyptus.atlassian.net/browse/GUI-1229
Update the comment to:

# Set the defailt option to be the first choice