Reverted the header change, added note in app/Config/email on how to enable it

- otherwise it might break custom e-mail configurations

app/Config/email.php

@@ -42,11 +42,11 @@
  */
 class EmailConfig {
 
+	// to set the return-path header, simply uncomment the line below and change you@localhost to the desired e-mail address
 	public $default = array(
 		'transport' => 'Mail',
-		//'from' => 'you@localhost',
 		'charset' => 'utf-8',
-		//'headerCharset' => 'utf-8',
+		//'additionalParameters' => '-f you@localhost'
 	);
 
 	public $smtp = array(

app/Model/User.php

@@ -572,11 +572,7 @@ class User extends AppModel {
 		}
 		$replyToLog = '';
 		if (!$failed) {
-			$Email = new CakeEmail(array(
-				'transport' => 'Mail',
-				'charset' => 'utf-8',
-				'additionalParameters' => '-f ' . Configure::read('MISP.email')
-			));
+			$Email = new CakeEmail();
 			
 			// If the e-mail is sent on behalf of a user, then we want the target user to be able to respond to the sender
 			// For this reason we should also attach the public key of the sender along with the message (if applicable)