Align uni01alpha CloudDomain and NeutronDnsDomain with other jobs

uni01alpha is the only adoption job using `CloudDomain: localdomain`
and `NeutronDnsDomain: 'openstackgate.local'`. It should be consistent
with other scenarios.

Author: renjingxiao

scenarios/uni01alpha.yaml

@@ -3,7 +3,7 @@ undercloud:
   config:
     - section: DEFAULT
       option: undercloud_hostname
-      value: undercloud.localdomain
+      value: undercloud.example.com
     - section: DEFAULT
       option: undercloud_timezone
       value: UTC
@@ -22,7 +22,7 @@ undercloud:
   undercloud_parameters_override: "uni01alpha/hieradata_overrides_undercloud.yaml"
   undercloud_parameters_defaults: "uni01alpha/undercloud_parameter_defaults.yaml"
   ctlplane_vip: 192.168.122.101
-cloud_domain: "localdomain"
+cloud_domain: "example.com"
 hostname_groups_map:
   # map ansible groups in the inventory to role hostname format for
   # 17.1 deployment

scenarios/uni01alpha/config_download.yaml

@@ -53,7 +53,7 @@ parameter_defaults:
   ComputeExtraConfig:
     nova::compute::libvirt::services::libvirt_virt_type: qemu
     nova::compute::libvirt::virt_type: qemu
-  NeutronDnsDomain: 'openstackgate.local'
+  NeutronDnsDomain: 'example.com'
   BarbicanSimpleCryptoGlobalDefault: true
   SwiftEncryptionEnabled: true
   Debug: true
@@ -64,19 +64,19 @@ parameter_defaults:
   NetworkerCount: 3
   NeutronGlobalPhysnetMtu: 1500
   CinderLVMLoopDeviceSize: 20480
-  CloudName: overcloud.localdomain
-  CloudNameInternal: overcloud.internalapi.localdomain
-  CloudNameStorage: overcloud.storage.localdomain
-  CloudNameStorageManagement: overcloud.storagemgmt.localdomain
-  CloudNameCtlplane: overcloud.ctlplane.localdomain
-  CloudDomain: localdomain
+  CloudName: overcloud.example.com
+  CloudNameInternal: overcloud.internalapi.example.com
+  CloudNameStorage: overcloud.storage.example.com
+  CloudNameStorageManagement: overcloud.storagemgmt.example.com
+  CloudNameCtlplane: overcloud.ctlplane.example.com
+  CloudDomain: example.com
   NetworkConfigWithAnsible: false
   ControllerHostnameFormat: '%stackname%-controller-%index%'
   ComputeHostnameFormat: '%stackname%-compute-%index%'
   NetworkerHostnameFormat: '%stackname%-networker-%index%'
   CtlplaneNetworkAttributes:
     network:
-      dns_domain: localdomain
+      dns_domain: example.com
       mtu: 1500
       name: ctlplane
       tags: