Description:
------------
Performing an update into a non-null longtext column using prepare syntax.  Example code works in php 5.0.x.  Upgraded to 5.1.x and it started entering variations of empty strings, 0, or 0000-00-00 depending on how much data I was trying to enter.  In a test that allows null values, it enters null.


(mysql 5.0.13 && mysql 5.0.15)

Reproduce code:
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CREATE TABLE test (col1 longtext not null);
<?php
$data = "whatever, some string";
$mysqli = new mysqli( HOST, USER, PASS, DB, PORT );
$query = "INSERT INTO test SET col1 = ?";
$prepared = $mysqli->prepare( $query );
$prepared->bind_param('s', $data );
$prepared->execute();
$prepared->close();
?>

Expected result:
----------------
contents of $data inserted into col1 of table.

Actual result:
--------------
SELECT col1 FROM test
shows one of three things:
0000-00-00
0
empty string