server/main_channel: reduce verbose agent data command
server/main_channel: reduce verbose agent data command

by using the new SPICE_DEBUG_LEVEL.

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