Add swift scenario tests

This tests swift as exercises do, trying common operations as:
 - create/delete a container;
 - add/delete object to a container;
 - list objects in the container;

Partial-Bug: #1023131
Cherry-picked from Id4b27ee70f420f7536b4c698eb1f3bba15dbd1e8

Change-Id: I6b95651684644344cd688d1ca1d6b3bd6bc70f01