Description:
------------
When executing an UPDATE query to a SQLite3 database, PDOStatement::rowCount() and PDO:exec() returns 0 instead of 1 or more when rows are updated in the database.

Reproduce code:
---------------
$db = new PDO('sqlite:crnl.db');
// PDO::exec() example
$sql = 'SELECT tags FROM blog_entries WHERE docid = 1';
$statement = $db->query($sql);
$row = $statement->fetch();
echo $row[0], "\n";
$sql = 'UPDATE blog_entries SET tags = \'test\' WHERE docid = 1';
echo $db->exec($sql), "\n";
$sql = 'SELECT tags FROM blog_entries WHERE docid = 1';
$statement = $db->query($sql);
$row = $statement->fetch();
echo $row[0], "\n";
// PDO:rowCount() example
$sql = 'UPDATE blog_entries SET tags = \'untest\' WHERE docid = 1';
echo $db->query($sql)->rowCount(), "\n";
$sql = 'SELECT tags FROM blog_entries WHERE docid = 1';
$statement = $db->query($sql);
$row = $statement->fetch();
echo $row[0], "\n";

Expected result:
----------------
untest
1
test
1
untest


Actual result:
--------------
untest
0
test
0
untest