variable_realm_refresh doesn't quite work with delete

1) have a variable overriden
2) delete that override
3) call variable_realm_refresh
4) variable still set to old value

Since global is active, and global contains the override,

  // Only update value if this is the current realm.
  if (variable_realm_status($realm_name) === $realm_key) {
    foreach (variable_realm_current() as $realm_controller) {
      $value = $realm_controller->getCurrentStore()->variable_get($variable_name, $value);
    }
  }

The first pass of this sets $value to the value in $conf, e.g.the overriden value that has since been deleted.