Deleted 4 old and low rated notes

Following were the 4 notes with a rating less than -5 and
are older than 1 year.

These notes represented 0.0% of the 16570 total user notes,
and have now been removed.

Rating | Note
-------+---------------------------------------------------------
   -6  | https://php.net/manual/en/session.idpassing.php#119597
   -6  | https://php.net/manual/en/function.mysql-connect.php#91965
   -6  | https://php.net/manual/en/memcache.installation.php#106175
   -6  | https://php.net/manual/en/function.is-file.php#119862