Add aggregates scenario test

The basic scenario for aggregates consists in the follow steps:
 - Creates an aggregate within an availability zone
 - Adds a host to the aggregate
 - Checks aggregate details
 - Updates aggregate's name
 - Removes host from aggregate
 - Deletes aggregate

Change-Id: I7a11b11468a5bbe85da4f6154308f7a5336c6919
Partial-bug: #1023131
Merge "Add aggregates scenario test"