Forcing redraw of snakview variation when changing the property

(bug 53157)
When selecting a property from the entityselector widget while another property is set already,
the snakview's cached property id is cleared to force redrawing the snakview variation.

Change-Id: I395bd7d851b355b69f1c8af06ce20a328af2c1d0
Merge "Forcing redraw of snakview variation when changing the property"