roles: Fix syntax for testing booleans

ansible-lint told me not to test equality with booleans using literal
"True" and "False", but it Ansible complains if I use "is True" also.
It seems that I need to adjust the syntax slightly.

roles/nginx/tasks/main.yml

@@ -71,7 +71,7 @@
 
 - name: Configure Let's Encrypt
   include_tasks: letsencrypt.yml
-  when: use_letsencrypt is defined and use_letsencrypt is True
+  when: use_letsencrypt is defined and use_letsencrypt
   tags: letsencrypt
 
 # vim: set ts=2 sw=2:

roles/nginx/tasks/wordpress.yml

@@ -3,12 +3,12 @@
 - block:
   - name: Install WordPress
     git: repo=https://github.com/WordPress/WordPress.git dest={{ nginx_root_prefix }}/{{ item.domain_name }}/wordpress version={{ item.wordpress_version }} depth=1 force=yes
-    when: item.has_wordpress is defined and item.has_wordpress is True
+    when: item.has_wordpress is defined and item.has_wordpress
     loop: "{{ nginx_vhosts }}"
 
   - name: Fix WordPress directory permissions
     file: path={{ nginx_root_prefix }}/{{ item.domain_name }} state=directory owner=nginx group=nginx recurse=yes
-    when: item.has_wordpress is defined and item.has_wordpress is True
+    when: item.has_wordpress is defined and item.has_wordpress
     loop: "{{ nginx_vhosts }}"
   tags: wordpress