Merge "Avoid possibility that integer result will overflow"

gerrit-server/src/main/java/com/google/gerrit/server/mail/SmtpEmailSender.java

@@ -152,7 +152,7 @@ public class SmtpEmailSender implements EmailSender {
     }
     if(expiryDays > 0) {
       Date expiry = new Date(System.currentTimeMillis() +
-        expiryDays * 24 * 60 * 60 * 1000 );
+        expiryDays * 24 * 60 * 60 * 1000L );
       setMissingHeader(hdrs, "Expiry-Date",
         new SimpleDateFormat("EEE, dd MMM yyyy HH:mm:ss Z").format(expiry));
     }