fix bugs in TableModel with QPSQL
fix bugs in TableModel with QPSQL

Change-Id: I7a201a1be2fb524372a171150c118ba23b0d347e
Reviewed-on: http://codereview.qt-users.jp/967
Reviewed-by: <42980d970444f9101663582e70cd53623b3238b4@gmail.com>
Tested-by: <42980d970444f9101663582e70cd53623b3238b4@gmail.com>

qt-users-jp/qmlplugins-database