In `WP_Filesystem_Base`, the constructor is a noop, so it shouldn't even be declared. Setting it implies that `parent::__construct()` should be called by its subclasses.

See #27881, #22234.


git-svn-id: https://develop.svn.wordpress.org/trunk@28529 602fd350-edb4-49c9-b593-d223f7449a82