Remove unused globals from `link-parse-opml.php` after [28743].

Props SergeyBiryukov.
Fixes #27881.


git-svn-id: https://develop.svn.wordpress.org/trunk@28786 602fd350-edb4-49c9-b593-d223f7449a82
Cleanup `wp_widget_rss_form()` after [28734]. "$$input used sanitized variables which contained actual values, unlike $inputs[$input] which in that context contains data about which input fields are hidden."

Props kovshenin.
Fixes #27881.


git-svn-id: https://develop.svn.wordpress.org/trunk@28787 602fd350-edb4-49c9-b593-d223f7449a82