Do not log contents of installed keypairs by default

This could put private key contents into the ansible log which is
undesireable.

Change-Id: Ic8e548b14e9fac26cf3b5a918479fdf8e0b24c6c
(cherry picked from commit a0471a3436)

roles/ssh_keypairs/tasks/standalone/install_ssh_key.yml

@@ -34,3 +34,4 @@
   loop: "{{ _ssh_key_slurp.results | default([]) }}"
   when: item.skipped is not defined
   ignore_errors: "{{ ansible_check_mode }}"
+  no_log: "{{ ssh_keypairs_no_log | default(True) }}"