Update WP theme paths only when template_root in releases_path (#840)

The update is needed only to fix the release subdirectory,
so it is safest to condition the update upon the releases_path
being in the template_root. This avoids overwriting less common
template_root values such as subdirectories of plugins, etc.

roles/deploy/hooks/finalize-after.yml

@@ -23,7 +23,7 @@
     command: wp option set {{ item }} {{ deploy_helper.new_release_path }}/web/wp/wp-content/themes
     args:
       chdir: "{{ deploy_helper.current_path }}"
-    when: wp_template_root.stdout != '' and wp_template_root.stdout != '/themes'
+    when: deploy_helper.releases_path in wp_template_root.stdout
     with_items:
       - stylesheet_root
       - template_root