Comments: Add back $req variable in comments_template().

The variables in `comments_template()` should never be assumed to be unused. This function includes the `comments.php` template file from the active theme or falls back to `theme-compat/comments.php`. This is why including a file within a function only brings pain and sorrow.

Reverts r36322.

See #35473.

git-svn-id: https://develop.svn.wordpress.org/trunk@36425 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-includes/comment-template.php

@@ -1256,6 +1256,8 @@ function comments_template( $file = '/comments.php', $separate_comments = false
 	if ( empty($file) )
 		$file = '/comments.php';
 
+	$req = get_option('require_name_email');
+
 	/*
 	 * Comment author information fetched from the comment cookies.
 	 */