aaa: Using collection instead of list

Bug-Url: https://bugzilla.redhat.com/show_bug.cgi?id=1120720
Change-Id: I5aec7cc3de308e5be3601b87c0543267fa5c018d
Topic: AAA
Signed-off-by: Yair Zaslavsky <yzaslavs@redhat.com>