IPN Spam due to incorrect transaction handling

[0xVavaldi]

IPN keeps spamming status 0 updates because it only accepts status 2 and 100.
throw new IpnIncompleteException($request['status_text'], $ipn); results in the IPN thinking it wasn't received correctly when in fact it was.

Example fix:

if ($is_complete) {
    return $ipn;
} else {
    throw new IpnIncompleteException($request['status_text'], $ipn);
}

Replaced by:
return $ipn;