QSqlTableModel::setData(): no longer autosubmit for OnRowChange

QSqlTableModel::setData(): no longer autosubmit for OnRowChange

The model can never do a good job of knowing when user moves to a
new row in the view. Faking it by detecting when another row
is changed was not a good solution because it cannot detect
when the last edited row is left.

Either the view should automatically submit when the user leaves
a row or the application should provide a way to submit.

This change made it possible to reuse the logic of flags() in
setData().

Change-Id: I2550e5b113bceba1a852fc21203babeca07c5748
Reviewed-by: Honglei Zhang <honglei.zhang@nokia.com>