server/tests: remove option from usage if AUTOMATED_TESTS is not configured
server/tests: remove option from usage if AUTOMATED_TESTS is not configured

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