uboot: (firmwareOdroidC2/C4) don't invoke patch tool, use patches = [] instead

https://github.com/NixOS/nixpkgs/blob/master/pkgs/stdenv/generic/setup.sh#L948
this can do it nicely.

Signed-off-by: Anton Arapov <anton@deadbeef.mx>

nixos/tests/etcd.nix

@@ -0,0 +1,25 @@
+# This test runs simple etcd node
+
+import ./make-test-python.nix ({ pkgs, ... } : {
+  name = "etcd";
+
+  meta = with pkgs.lib.maintainers; {
+    maintainers = [ offline ];
+  };
+
+  nodes = {
+    node = { ... }: {
+      services.etcd.enable = true;
+    };
+  };
+
+  testScript = ''
+    with subtest("should start etcd node"):
+        node.start()
+        node.wait_for_unit("etcd.service")
+
+    with subtest("should write and read some values to etcd"):
+        node.succeed("etcdctl set /foo/bar 'Hello world'")
+        node.succeed("etcdctl get /foo/bar | grep 'Hello world'")
+  '';
+})