Change libvirt default to kvm

Also only list qemu and kvm as options, as those are the only
ones we support, even though others would be passed through
and might work.

Change-Id: Ifaedd7d3d2cc5fd03465b9110f865daaca6e9fd0
Closes-bug: https://bugzilla.redhat.com/show_bug.cgi?id=1243601

doc/source/command-objects/overcloud.rst

@@ -144,9 +144,9 @@ Deploy an overcloud stack
     An ordered list of extension driver entrypoints to be loaded from the
     neutron.ml2.extension_drivers namespace.
 
-.. option:: --libvirt-type [kvm|lxc|qemu|uml|xen|parallels]
+.. option:: --libvirt-type {kvm,qemu}
 
-    Libvirt domain type. (default: qemu)
+    Libvirt domain type. (default: kvm)
 
 .. option:: --ntp-server <ip-address>
 

rdomanager_oscplugin/tests/v1/overcloud_deploy/test_overcloud_deploy.py

@@ -298,7 +298,7 @@ class TestDeployOvercloud(fakes.TestDeployOvercloud):
             'NeutronTunnelIdRanges': '1:1000',
             'NeutronTunnelTypes': 'gre',
             'NeutronVniRanges': '1:1000',
-            'NovaComputeLibvirtType': 'qemu',
+            'NovaComputeLibvirtType': 'kvm',
             'NovaImage': 'overcloud-full',
             'NovaPassword': 'password',
             'NtpServer': '',

rdomanager_oscplugin/v1/overcloud_deploy.py

@@ -81,7 +81,7 @@ PARAMETERS = {
 }
 
 NEW_STACK_PARAMETERS = {
-    'NovaComputeLibvirtType': 'qemu',
+    'NovaComputeLibvirtType': 'kvm',
     'NeutronTunnelIdRanges': '1:1000',
     'NeutronVniRanges': '1:1000',
     'NeutronEnableTunnelling': 'True',
@@ -793,8 +793,9 @@ class DeployOvercloud(command.Command):
                                    'entrypoints to be loaded from the '
                                    'neutron.ml2.extension_drivers namespace.'))
         parser.add_argument('--libvirt-type',
-                            help=_('Libvirt domain type. (default: qemu) '
-                                   '[qemu|kvm|lxc|uml|xen|parallels]'))
+                            default='kvm',
+                            choices=['kvm', 'qemu'],
+                            help=_('Libvirt domain type. (default: kvm)'))
         parser.add_argument('--ntp-server',
                             help=_('The NTP for overcloud nodes.'))
         parser.add_argument(