Update spice-protocol to 0.12.6
Update spice-protocol to 0.12.6

freedesktop-unofficial-mirror/spice__spice-common,elmarco/spice-common,freedesktop-unofficial-mirror/spice__spice-common,fgouget/spice-common,fgouget/spice-common,elmarco/spice-common,freedesktop-unofficial-mirror/spice__spice-common,freedesktop-unofficial-mirror/spice__spice-common,elmarco/spice-common,SPICE/spice-common,elmarco/spice-common,Fantu/spice-common,Fantu/spice-common,SPICE/spice-common,fgouget/spice-common,Fantu/spice-common,SPICE/spice-common,Fantu/spice-common,fgouget/spice-common