Handle libvirt modular daemon container names

Tripleo has updated libvirt container organization to breakup libvirt
processes that were normally all contained in nova_libvirt across
multiple new containers. [1] When interacting with virsh downstream
tests now need to access container 'nova_virtqemud' instead of
nova_libvirtd.  This update allows the container name for libvirt to be
a parameter that will default to nova_libvirtd if nothing is provided.

[1] bbdad5c27e

Change-Id: I5b4e5323c7734968cadd9736abd5ba92b5c5cea6

whitebox_tempest_plugin/config.py

@@ -173,6 +173,11 @@ libvirt_opts = [
         help='Similar to the mask_command option, this config options sets '
              'the command to unmask libvirt. If set, it will be run before '
              'every start command.'),
+    cfg.StrOpt(
+        'libvirt_container_name',
+        default="nova_libvirt",
+        help='The container name to use when needing to interact with the '
+             'respective virsh command of the compute host'),
 ]
 
 database_group = cfg.OptGroup(

whitebox_tempest_plugin/services/clients.py

@@ -59,17 +59,24 @@ class SSHClient(object):
 class VirshXMLClient(SSHClient):
     """A client to obtain libvirt XML from a remote host."""
 
+    def __init__(self, ctlplane_address):
+        super(VirshXMLClient, self).__init__(ctlplane_address)
+        self.container_name = CONF.whitebox_libvirt.libvirt_container_name
+
     def dumpxml(self, domain):
         command = 'virsh dumpxml %s' % domain
-        return self.execute(command, container_name='nova_libvirt', sudo=True)
+        return self.execute(
+            command, container_name=self.container_name, sudo=True)
 
     def capabilities(self):
         command = 'virsh capabilities'
-        return self.execute(command, container_name='nova_libvirt', sudo=True)
+        return self.execute(
+            command, container_name=self.container_name, sudo=True)
 
     def domblklist(self, server_id):
         command = 'virsh domblklist %s' % server_id
-        return self.execute(command, container_name='nova_libvirt', sudo=True)
+        return self.execute(
+            command, container_name=self.container_name, sudo=True)
 
 
 class LogParserClient(SSHClient):