plugins/dmxusb: use absolute line indices when destroying a pro widget
plugins/dmxusb: use absolute line indices when destroying a pro widget

mcallegari/qlcplus,kripton/qlcplus,plugz/qlcplus,mcallegari/qlcplus,mcallegari/qlcplus,mcallegari/qlcplus,plugz/qlcplus,plugz/qlcplus,plugz/qlcplus,mcallegari/qlcplus,sbenejam/qlcplus,kripton/qlcplus,sbenejam/qlcplus,sbenejam/qlcplus,plugz/qlcplus,kripton/qlcplus,kripton/qlcplus,sbenejam/qlcplus,sbenejam/qlcplus,mcallegari/qlcplus,plugz/qlcplus,mcallegari/qlcplus,kripton/qlcplus,sbenejam/qlcplus,sbenejam/qlcplus,kripton/qlcplus,plugz/qlcplus,kripton/qlcplus