MDL-40100 cache: removed unneeded includes from add instance forms

cache/stores/file/addinstanceform.php

@@ -27,7 +27,6 @@
  */
 
 require_once($CFG->dirroot.'/cache/forms.php');
-require_once($CFG->dirroot.'/cache/stores/file/lib.php');
 
 /**
  * Form for adding a file instance.

cache/stores/memcache/addinstanceform.php

@@ -27,7 +27,6 @@
 defined('MOODLE_INTERNAL') || die();
 
 require_once($CFG->dirroot.'/cache/forms.php');
-require_once($CFG->dirroot.'/cache/stores/memcached/lib.php');
 
 /**
  * Form for adding a memcache instance.

cache/stores/mongodb/addinstanceform.php

@@ -35,7 +35,6 @@ defined('MOODLE_INTERNAL') || die();
 
 // Include the necessary evils.
 require_once($CFG->dirroot.'/cache/forms.php');
-require_once($CFG->dirroot.'/cache/stores/mongodb/lib.php');
 
 /**
  * The form to add an instance of the MongoDB store to the system.