Switch to using setup instead of hostvars

hostvars can potentially leak secrets. setup doesn't, and records what
we're interested in, which is the information ansible knows about the
remote host.

Change-Id: Ice585cb3beddf4e3ecc1e692ecf4e7da8c5754b8

roles/validate-host/README.rst

@@ -1,3 +1 @@
-Output all of the Ansible variables for the host
-
-This is unsafe to run in Trusted jobs as it will write any secrets to the log.
+Log information about the remote build host

roles/validate-host/tasks/main.yaml

@@ -8,11 +8,15 @@
     path: "{{ zuul_info_dir }}"
     state: directory
 
+- name: Collect information about the host
+  setup:
+  register: setupinfo
+
 - name: Write out all ansible variables/facts known for each host
   delegate_to: localhost
   template:
-    dest: "{{ zuul_info_dir }}/ansible-hostvars.{{ inventory_hostname }}.yaml"
-    src: templates/ansible-hostvars.j2
+    dest: "{{ zuul_info_dir }}/host-info.{{ inventory_hostname }}.yaml"
+    src: templates/host-info.j2
 
 - name: Collect information about zuul worker
   zuul_debug_info:

roles/validate-host/templates/ansible-hostvars.j2

@@ -1 +0,0 @@
-{{ hostvars[inventory_hostname] | to_nice_yaml(indent=2) }}

roles/validate-host/templates/host-info.j2

@@ -0,0 +1 @@
+{{ setupinfo | to_nice_yaml(indent=2) }}