Collect logs from testing

It is helpful to have logs to debug failures.

Change-Id: I3d5170713a031dc8ccb4772a7778bec1e63ffa15
Signed-off-by: Paul Belanger <pabelanger@redhat.com>

.zuul.yaml

@@ -1,6 +1,7 @@
 - job:
     name: ansible-role-nodepool
     run: tests/test.yaml
+    post-run: tests/collect-logs.yaml
     required-projects:
       - name: openstack-infra/nodepool
         override-branch: feature/zuulv3

tests/collect-logs.yaml

@@ -0,0 +1,10 @@
+- hosts: all
+  tasks:
+    - name: Collect nodepool log files
+      synchronize:
+        dest: "{{ zuul.executor.log_root }}/logs"
+        mode: pull
+        rsync_opts:
+          - "--relative"
+        src: /var/log/nodepool
+        verify_host: true