Description:
------------
Second prepare() returns no object so execute() ends with
PHP Fatal error:  Call to a member function execute() on a non-object in




Reproduce code:
---------------
$stmt = $dbh->prepare("SELECT d_pk FROM d WHERE t=1");
print_r($stmt);
$stmt->execute();

$stmt = $dbh->prepare("SELECT d_pk FROM d WHERE t=2");
print_r($stmt);
$stmt->execute();


Expected result:
----------------
PDOStatement Object
(
    [queryString] => SELECT d_pk FROM d WHERE type=1
)
PDOStatement Object
(
    [queryString] => SELECT d_pk FROM d WHERE type=2
)


Actual result:
--------------
PDOStatement Object
(
    [queryString] => SELECT d_pk FROM d WHERE type=1
)
PHP Fatal error:  Call to a member function execute() on a non-object in