server: avoid creating a stream from traces more than once for the same drawable
server: avoid creating a stream from traces more than once for the same drawable

could have caused ASSERT(!drawable->stream) in red_create_stream

alon/spice-server,fgouget/spice,Fantu/spice,SPICE/spice,freedesktop-unofficial-mirror/spice__spice,virtualAMP/spiceplay,SPICE/spice,virtualAMP/spiceplay,freedesktop-unofficial-mirror/spice__spice,SPICE/spice,freedesktop-unofficial-mirror/spice__spice,dezelin/spice,elmarco/spice,fgouget/spice,mathslinux/spice,freedesktop-unofficial-mirror/spice__spice,Fantu/spice,mathslinux/spice,ya-mouse/spice,alon/spice-server,fgouget/spice,fgouget/spice,ya-mouse/spice,elmarco/spice,virtualAMP/spiceplay,mathslinux/spice,elmarco/spice,ya-mouse/spice,elmarco/spice,elmarco/spice,dezelin/spice,mathslinux/spice,Fantu/spice,virtualAMP/spiceplay,alon/spice-server,freedesktop-unofficial-mirror/spice__spice,alon/spice-server,dezelin/spice,Fantu/spice,mathslinux/spice,dezelin/spice,dezelin/spice,alon/spice-server