WIP: Namespace host_otp variable

By namespacing the variable with the project name, we clarify what
exactly we're providing if people want to invoke the
ipa-server-register-undercloud.yaml tasks from another ansible playbook
and fish the OTP out using a variable name.

Change-Id: If053250937ce76705cdd5084d76869edca8404ce

tripleo_ipa/playbooks/README.md

@@ -21,6 +21,10 @@ ok: [localhost] => {
     ]
 }
 ```
+
+If you're including this playbook via another ansible execution, you can fetch
+the one-time password via the ``tripleo_ipa_host_otp`` variable.
+
 > This playbook does not require an active Kerberos token.
 
 > This playbook needs to be run once per openstack deployment.

tripleo_ipa/playbooks/ipa-server-register-undercloud.yaml

@@ -57,11 +57,11 @@
         fqdn: "{{ undercloud_fqdn }}"
         random_password: true
         force: true
-      register: host_otp
+      register: tripleo_ipa_host_otp
 
     - name: provide OTP generated by IPA server
       debug:
         msg:
-          - "The OTP provided by the IPA server is {{ host_otp.host.randompassword }}"
+          - "The OTP provided by the IPA server is {{ tripleo_ipa_host_otp.host.randompassword }}"
           - "Please add the following to your undercloud.conf:"
-          - "ipa_otp = {{ host_otp.host.randompassword }}"
+          - "ipa_otp = {{ tripleo_ipa_host_otp.host.randompassword }}"