fix update error
fix update error

Change-Id: I6601be133e8f6fb146a1b9730e94c47d31ecf5c5
Reviewed-on: http://cr.qtquick.me/580
Reviewed-by: Tasuku Suzuki <42980d970444f9101663582e70cd53623b3238b4@gmail.com>
Tested-by: Tasuku Suzuki <42980d970444f9101663582e70cd53623b3238b4@gmail.com>

qt-users-jp/qmlplugins-database