ansible-inventories/arocom#192 Fix the test if Redis is available

templates/d8_settings.php

@@ -60,7 +60,7 @@ $config_directories['{{ directory }}'] = 'sites/{{ item.shortname|default("defau
 {% endfor %}
 
 // Set redis configuration.
-if (extension_loaded('redis')) {
+if (file_exists('modules/contrib/redis/redis.info.yml')) {
   // Set Redis as the default backend for any cache bin not otherwise specified.
   $settings['redis.connection']['interface'] = 'PhpRedis';
   $settings['cache']['default'] = 'cache.backend.redis';