bugfix for QQMail link display error.

Function "retrieve_password" will send user an e-mail, if user's e-mail address ends of qq.com, a symbol will be appended to the end of the link which is in the mail, eg.: 
`/wp-login.php?action=rp&key=YyV********5jKj&login=soulteary>`

detail:
http://www.soulteary.com/2013/12/12/wordpress-for-sae-send-mail.html