Fix hardcoded gateway in IPV6 subnet api tests

This patch removes the hardcoding and calculates the Gateway-ip
based on the tenant_network_v6_cidr value.

Change-Id: Iee4c450714caf49d6753d9455e6ab3698b64340d
Closes-Bug: #1318962
Rename Marconi to Zaqar

Due to copyright issues Marconi is renamed to Zaqar. This patch updates
all Marconi references to Zaqar.

Change-Id: Ib37b95d99bbfc666e1a3a17174d87804ecd0649e
Extract SwiftScenarioTest class to manager

This allows the class to be used in other swift tests.

Change-Id: I94233ad529bd96fa07e72cf2dcbc9e415986a069
Merge "Fix hardcoded gateway in IPV6 subnet api tests"
Merge "Extract SwiftScenarioTest class to manager"
Merge "Rename Marconi to Zaqar"
Merge branch 'master' of https://github.com/openstack/tempest