Add --quiet flag to CI diagnostics collection

This ensures that our CI logs are neat, and not full of file rsync
output.

Change-Id: Ic3bad1baa1b2f8639c8ce848a60c024d8c22e8d0

roles/kayobe-diagnostics/tasks/post.yml

@@ -22,3 +22,7 @@
     src: "{{ kayobe_diagnostics_log_dir }}/"
     dest: "{{ kayobe_diagnostics_executor_log_dir }}/"
     mode: pull
+    copy_links: true
+    verify_host: true
+    rsync_opts:
+      - "--quiet"