fixed randome string generation when cloning a message
fixed randome string generation when cloning a message

gencer/swiftmailer,jamesggordon/swiftmailer,tweakers-dev/swiftmailer,denpamusic/swiftmailer,voku/swiftmailer,swiftmailer/swiftmailer,c960657/swiftmailer,michabbb-backup/swiftmailer,denpamusic/swiftmailer,Rotzbua/swiftmailer,tweakers-dev/swiftmailer,jamesggordon/swiftmailer,michabbb-backup/swiftmailer,Rotzbua/swiftmailer,voku/swiftmailer,gencer/swiftmailer,c960657/swiftmailer,swiftmailer/swiftmailer