MDL-46509 enrol: fix usage of incorrect capability check

enrol/ldap/lib.php

@@ -108,7 +108,7 @@ class enrol_ldap_plugin extends enrol_plugin {
      */
     public function can_delete_instance($instance) {
         $context = context_course::instance($instance->courseid);
-        if (!has_capability('enrol/ldap:config', $context)) {
+        if (!has_capability('enrol/ldap:manage', $context)) {
             return false;
         }