ad-auth: add nsswitch configuration

ad-auth/tasks/sssd.yml

@@ -100,6 +100,15 @@
   tags:
     - sssd
 
+# taken out of Debian's post install hooks
+- name: ensure sssd is configured in nsswitch.conf
+  shell: "sed -i --regexp-extended '/^(passwd|group|shadow|netgroup|services):/ {
+  /\\bsss\\b/! s/$/ sss/  } ' /etc/nsswitch.conf"
+  args:
+    warn: false
+  tags:
+    - sssd
+
 - name: ensure sssd is enabled and running
   service:
     name: sssd