Also install memcached for PHP7

tasks/main.yml

@@ -13,8 +13,7 @@
       state='installed'
       update_cache=yes
     with_items:
-      - php5-memcached
+      - php{{ (php_version|default('5.5') != '7') | ternary('5','') }}-memcached
       - memcached
-    when: php_version|default('5.5') != '7'
 
   when: '"memcache" not in excluded_roles'