Description:
------------
Calling ob_clean() after starting the ob_gzhandler screws up. ob_get_clean() doesn't seem to behave perfectly either.

There seem to be two problems:
* The gzip headers gets lost or is incorrect.
* The Content-Encoding header can be set even if the data is not gzip'ed (See test script 2)

Test script:
---------------
<?php
  ob_start('ob_gzhandler');
  // Do anything, doesn't matter whether you output anything or give an empty response.
  ob_clean();
?>

or
<?php
  ob_start('ob_gzhandler');
  echo "Hello world.";
  print ob_get_clean();
?>

Expected result:
----------------
HTTP/1.1 200 OK
Date: Tue, 11 Oct 2011 14:32:12 GMT
Server: Apache
Content-Encoding: gzip
Vary: Accept-Encoding
Content-Length: 0
Connection: close
Content-Type: text/html; charset=utf-8

Connection closed by foreign host.


Actual result:
--------------
HTTP/1.1 200 OK
Date: Tue, 11 Oct 2011 14:32:12 GMT
Server: Apache
Content-Encoding: gzip
Vary: Accept-Encoding
Content-Length: 0
Connection: close
Content-Type: text/html; charset=utf-8

[some data]
Connection closed by foreign host.