Added neutron cli test case for vpnaas

vpn_list,ikepolicy,ipsecpolicy,ipsec_site

Change-Id: If61eb1506da464b0e173ef63c4dbccdd8f757616
Add internal methods for setting compute clients

If disabling XML tests on compute API tests by the config item
"xml_api_v2", we need to switch XML clients to JSON clients on
the other project API tests. But current code is difficult to
switch, because compute clients are many and the order is mess.
This patch adds internal methods to set compute clients for
cleanup.

Change-Id: I62bf48845c289b86f1af71e9fbf71e45b509a43d
Merge "Added neutron cli test case for vpnaas"
Merge "Add internal methods for setting compute clients"