Fix PHP warning when responding to a message with many Return-Path headers (#1489136)

Conflicts:

	CHANGELOG

CHANGELOG

@@ -1,6 +1,7 @@
 CHANGELOG Roundcube Webmail
 ===========================
 
+- Fix PHP warning when responding to a message with many Return-Path headers (#1489136)
 - Fix unintentional compose window resize (#1489114)
 - Fix performance regression in text wrapping function (#1489133)
 - Fix connection to posgtres db using unix socket (#1489132)

program/steps/mail/func.inc

@@ -1803,9 +1803,12 @@ function rcmail_identity_select($MESSAGE, $identities = null, $compose_mode = 'r
     // Try Return-Path
     if ($from_idx === null && ($return_path = $MESSAGE->headers->others['return-path'])) {
         foreach ($identities as $idx => $ident) {
-            if (strpos($return_path, str_replace('@', '=', $ident['email_ascii']).'@') !== false) {
-                $from_idx = $idx;
-                break;
+            $ident = str_replace('@', '=', $ident['email_ascii']) . '@';
+            foreach ((array)$return_path as $path) {
+                if (strpos($path, $ident) !== false) {
+                    $from_idx = $idx;
+                    break 2;
+                }
             }
         }
     }