Timeline: Emit heightChanged() when empty changes
Timeline: Emit heightChanged() when empty changes

The height of a model is 0 if the model is empty. Thus, when clearing
we have to emit heightChanged().

Change-Id: I6f05c2a32cff648d6aa8e623e17aebe9ae4fcb5c
Task-number: QTCREATORBUG-14507
Reviewed-by: Joerg Bornemann <47777b9406dbddd02a3fdca8341789a013805a11@theqtcompany.com>

martyone/sailfish-qtcreator,xianian/qt-creator,xianian/qt-creator,xianian/qt-creator,xianian/qt-creator,martyone/sailfish-qtcreator,martyone/sailfish-qtcreator,martyone/sailfish-qtcreator,xianian/qt-creator,martyone/sailfish-qtcreator,martyone/sailfish-qtcreator,martyone/sailfish-qtcreator,xianian/qt-creator,xianian/qt-creator,martyone/sailfish-qtcreator,xianian/qt-creator,martyone/sailfish-qtcreator,xianian/qt-creator