testing: Suppress errors when checking for running hosts

If libvirt is not running virsh can't connect to it and will complain that
the socket does not exist.

testing/scripts/function.sh

@@ -163,7 +163,7 @@ running_any()
 	command -v virsh >/dev/null || return 1
 	for host in $*
 	do
-		virsh list --name | grep "^$host$" >/dev/null && return 0
+		virsh list --name 2>/dev/null | grep "^$host$" >/dev/null && return 0
 	done
 	return 1
 }