Description:
------------
IMAP connection throws notices on failure which are not suppressed even 
by @

Notice: Unknown: Retrying PLAIN authentication after Login failed. 
(errflg=1) in Unknown on line 0

Notice: Unknown: Retrying PLAIN authentication after Login failed. 
(errflg=1) in Unknown on line 0

Notice: Unknown: Can not authenticate to IMAP server: Login failed. 
(errflg=2) in Unknown on line 0<

when IMAP command fails, the follow errors are returned and can not be 
suppressed, by changing log status or by using @ infront of the lines

Reproduce code:
---------------
<?php

$mailbox = 'INBOX';
$username = 'emaildoesntexist@example.org';
$password = 'orpasswordnotcorrect';

imap_open ($mailbox, $username, $password);

// regardless of log settings, assuming the imap account is invalid,
// errors are returned to the client 

?>

Expected result:
----------------
should be able to stop errors from being returned to client
should listed to logging levels

Actual result:
--------------
errors are returned to webuser
changing log levels does not affect it