Fix container image build issues with letsencrypt

The kolla_enable_letsencrypt variable was undefined, which was causing
overcloud container image build to fail when the variable was not
defined in Kayobe configuration.

The bool filter was missing for kolla_enable_letsencrypt, which was
causing letsencrypt images to be built when kolla_enable_letsencrypt was
set to "false" or "no".

Change-Id: I234b7a0434ba3d533a66b766331fd489078fbcf8

ansible/inventory/group_vars/all/kolla

@@ -162,7 +162,7 @@ overcloud_container_image_regex_map:
   - regex: ^haproxy$
     enabled: "{{ kolla_enable_haproxy | bool }}"
   - regex: ^haproxy-ssh$
-    enabled: "{{ kolla_enable_letsencrypt }}"
+    enabled: "{{ kolla_enable_letsencrypt | bool }}"
   - regex: ^heat
     enabled: "{{ kolla_enable_heat | bool }}"
   - regex: ^horizon
@@ -184,7 +184,7 @@ overcloud_container_image_regex_map:
   - regex: ^kuryr
     enabled: "{{ kolla_enable_kuryr | bool }}"
   - regex: ^letsencrypt
-    enabled: "{{ kolla_enable_letsencrypt }}"
+    enabled: "{{ kolla_enable_letsencrypt | bool }}"
   - regex: ^magnum
     enabled: "{{ kolla_enable_magnum | bool }}"
   - regex: ^manila
@@ -529,6 +529,7 @@ kolla_enable_ironic: "no"
 kolla_enable_ironic_neutron_agent: "{{ kolla_enable_neutron | bool and kolla_enable_ironic | bool }}"
 kolla_enable_iscsid: "{{ kolla_enable_cinder | bool and kolla_enable_cinder_backend_iscsi | bool }}"
 kolla_enable_kuryr: "no"
+kolla_enable_letsencrypt: "no"
 kolla_enable_magnum: "no"
 kolla_enable_manila: "no"
 kolla_enable_masakari: "no"

releasenotes/notes/fix-kolla-enable-letsencrypt-8e8746560be575ac.yaml

@@ -0,0 +1,6 @@
+---
+fixes:
+  - |
+    Fixes bugs with the ``kolla_enable_letsencrypt`` variable which were
+    causing overcloud container image build to fail, or to include
+    ``letsencrypt`` images when disabled.