Description:
------------
opening file in append mode and writing to file wrote data twice to 
file

Reproduce code:
---------------
<?php
$filename = 'test.txt';
$somecontent = "Add this to the file\n";

// In our example we're opening $filename in append mode.
// The file pointer is at the bottom of the file hence
// that's where $somecontent will go when we fwrite() it.
if (!$handle = fopen($filename, 'a')) {
  echo "Cannot open file ($filename)";
  exit;
}

// Write $somecontent to our opened file.
if (fwrite($handle, $somecontent) === FALSE) {
  echo "Cannot write to file ($filename)";
  exit;
}

fclose($handle);

?>

Expected result:
----------------
in 'test.txt':
Add this to the file\n



Actual result:
--------------
in 'test.txt':
Add this to the file\nAdd this to the file\n