Fix broken k8s installs

Related: https://github.com/ansible/awx/issues/5205

The following commit introduced this bug:
712b07c136 (diff-a2ef2d6347894a92a6b882e3793fb06c)

installer/roles/kubernetes/templates/deployment.yml.j2

@@ -203,6 +203,11 @@ spec:
               subPath: settings.py
               readOnly: true
 
+            - name: {{ kubernetes_deployment_name }}-nginx-config
+              mountPath: /etc/nginx/nginx.conf
+              subPath: nginx.conf
+              readOnly: true
+
             - name: "{{ kubernetes_deployment_name }}-application-credentials"
               mountPath: "/etc/tower/conf.d/"
               readOnly: true
@@ -390,6 +395,13 @@ spec:
               - key: {{ kubernetes_deployment_name }}_settings
                 path: settings.py
 
+        - name: {{ kubernetes_deployment_name }}-nginx-config
+          configMap:
+            name: {{ kubernetes_deployment_name }}-config
+            items:
+              - key: {{ kubernetes_deployment_name }}_nginx_conf
+                path: nginx.conf
+
         - name: "{{ kubernetes_deployment_name }}-application-credentials"
           secret:
             secretName: "{{ kubernetes_deployment_name }}-secrets"