Fix emission of QQmlListModel::rowsAboutToBeXxx() signals

Call beginInsertRows(), beginMoveRows() and beginRemoveRows() before
the change to ensure that rowsAboutToBeInserted(), rowsAboutToBeMoved()
and rowsAboutToBeRemoved() get emitted before the change as appropriate.

NOTE: This patch solves the problem for the most common use case, when
ListModel is used without WorkerScript. QQmlListModelWorkerAgent needs
similar changes in order to fix the signals when ListModel is used with
WorkerScript (QTBUG-39321).

Task-number: QTBUG-39279
Change-Id: Idec5167d70b242f6f7d8b7cff008e130afc62505
Reviewed-by: Alan Alpert <aalpert@blackberry.com>
Don't add the database before verification

The local storage facility exposed to QML has a bug; if you attempt to
open a versioned connection, the version is wrong, and you try to handle
that error, the connection is still stored in a connection pool, but in
an unopened state.  The next time you attempt to connect, no matter if
you have the version right or not, the database handle will complain
about being unopened.

See also http://qt-project.org/forums/viewthread/38458/

Task-number: QTBUG-38543
Change-Id: I921b94621009f4968144e1cc513c17b4924a792a
Reviewed-by: Lars Knoll <lars.knoll@digia.com>
Reviewed-by: Alan Alpert (Personal) <416365416c@gmail.com>