Fix crash when closing while recording
Fix crash when closing while recording

First notify about disconnection before resetting the channel data.
An audio recording task might expect the channel to be in a ready
state otherwise, for example.

https://bugzilla.redhat.com/show_bug.cgi?id=810247

elmarco/spice-gtk,SPICE/spice-gtk,SPICE/spice-gtk,Fantu/spice-gtk,guodong/spice-gtk,dezelin/spice-gtk,fgouget/spice-gtk,fgouget/spice-gtk,guodong/spice-gtk,freedesktop-unofficial-mirror/spice__spice-gtk,guodong/spice-gtk,elmarco/spice-gtk,freedesktop-unofficial-mirror/spice__spice-gtk,flexVDI/spice-gtk,fgouget/spice-gtk,elmarco/spice-gtk,dezelin/spice-gtk,SPICE/spice-gtk,mathslinux/spice-gtk,flexVDI/spice-gtk,mathslinux/spice-gtk,dezelin/spice-gtk,Fantu/spice-gtk,guodong/spice-gtk,SPICE/spice-gtk,freedesktop-unofficial-mirror/spice__spice-gtk,elmarco/spice-gtk,mathslinux/spice-gtk,mathslinux/spice-gtk,Fantu/spice-gtk,Fantu/spice-gtk,freedesktop-unofficial-mirror/spice__spice-gtk,dezelin/spice-gtk