Bootstrap: after r38409 and r38410, revert r38402 which reverted r38399.

This fixes the paths in `wp-vendor/` that were including `src`. I want to drop this in so we can find out what else will break.

See #36335.


git-svn-id: https://develop.svn.wordpress.org/trunk@38411 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-includes/pluggable.php

@@ -211,7 +211,6 @@ function wp_mail( $to, $subject, $message, $headers = '', $attachments = array()
 	// (Re)create it, if it's gone missing
 	if ( ! ( $phpmailer instanceof PHPMailer ) ) {
 		require_once ABSPATH . WPINC . '/class-phpmailer.php';
-		require_once ABSPATH . WPINC . '/class-smtp.php';
 		$phpmailer = new PHPMailer( true );
 	}