Connect openstack_pki_regen_ca variable to pki role

This was missing where the pki role is called but was documented
as a usable option.

Change-Id: Icde65f696627237fd55b5cfb69943f184f419bba

playbooks/certificate-authority.yml

@@ -25,4 +25,5 @@
       vars:
         pki_dir: "{{ openstack_pki_dir }}"
         pki_create_ca: "{{ openstack_pki_authorities | default([]) | length > 0 }}"
+        pki_regen_ca: "{{ openstack_pki_regen_ca }}"
         pki_authorities: "{{ openstack_pki_authorities }}"