Mail: Don't set Sender field when setting From.

[38058] changed `wp_mail()` so that it used PHPMailer's `setFrom()`
method rather than setting the From and FromName headers directly. See
behavior of setting the `Sender` field. This causes `mail` to be
called with the `-f` flag, which causes outgoing email to fail on some
server environments.

Merges [38286] to the 4.6 branch.

Props Clorith, iandunn, DrewAPicture.
Fixes #37736. 

Built from https://develop.svn.wordpress.org/branches/4.6@38287


git-svn-id: http://core.svn.wordpress.org/branches/4.6@38228 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/pluggable.php

@@ -349,7 +349,7 @@ function wp_mail( $to, $subject, $message, $headers = '', $attachments = array()
 	 */
 	$from_name = apply_filters( 'wp_mail_from_name', $from_name );
 
-	$phpmailer->setFrom( $from_email, $from_name );
+	$phpmailer->setFrom( $from_email, $from_name, false );
 
 	// Set destination addresses
 	if ( !is_array( $to ) )

wp-includes/version.php

@@ -4,7 +4,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '4.6.1-alpha-38271';
+$wp_version = '4.6.1-alpha-38287';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.