Description:
------------
Multiple of our perfectly working scripts for years suddenly stopped working right after the automatic update to php 5.6.28. Reverting back to a php 5.5 version make everything work as it should again. sftp linux command is working perfectly, everything works as it should from any other environment (multiple tests done) etc. Right now everything points out php 5.6.28 to be the culprit.

It seems that SSH2 connects and even log in BUT there is not way to access ANY folder level even though access is granted and everything works fine with other php versions. 

Example of error thrown:
fopen(ssh2.sftp://Resource id #3/./): failed to open stream: operation failed in...
scandir(ssh2.sftp://Resource id #3/upload/): failed to open dir: operation failed in....
scandir(): (errno 11): Resource temporarily unavailable in...

This has caused us a headache and although sftp is maybe not the most popular protocol I'm surprise that we did not find any post regarding this issue online.

php released this version on Nov. 10th and our CPanel automatically updated on Nov. 15th. Since then our log clearly showed that all sftp connection were unable to feed.

Test script:
---------------
...

if ($connection = ssh2_connect($ftp_server, $ftp_port)) {
    echo "Connected to SFTP server.";
} else {
    echo "Can't connect to SFTP server.";
}
if (ssh2_auth_password($connection, $ftp_username, $ftp_password)) {
    echo "Logged to SFTP server.";
} else {
    echo "Can't log to SFTP server.";
}

$sftp = ssh2_sftp($connection);

$stream = fopen("ssh2.sftp://$sftp/./", 'r');

$files = array_diff(scandir('ssh2.sftp://' . $sftp . $ftp_dir), array('..', '.'));

echo "<pre>";
print_r($files);
echo "</pre>";

...