nixos/lock-kernel-modules: fix typo in unitConfig

I managed to miss this one somehow ... meh

Changed files
+1 -1
nixos
modules
+1 -1
nixos/modules/security/lock-kernel-modules.nix
···
script = "echo -n 1 > /proc/sys/kernel/modules_disabled";
-
unitConfig.ConditionPathIsWritable = "/proc/sys/kernel";
+
unitConfig.ConditionPathIsReadWrite = "/proc/sys/kernel";
serviceConfig = {
Type = "oneshot";