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>

pkgs/servers/monitoring/do-agent/default.nix

@@ -0,0 +1,38 @@
+{ lib, buildGoModule, fetchFromGitHub }:
+
+buildGoModule rec {
+  pname = "do-agent";
+  version = "3.13.0";
+
+  src = fetchFromGitHub {
+    owner = "digitalocean";
+    repo = "do-agent";
+    rev = version;
+    sha256 = "sha256-GJwNJRH7Ib4b3ZP0JHDMZD6h/AZvpRpIaZUDtnLFVoc=";
+  };
+
+  ldflags = [
+    "-X main.version=${version}"
+  ];
+
+  vendorSha256 = null;
+
+  doCheck = false;
+
+  postInstall = ''
+    install -Dm444 -t $out/lib/systemd/system $src/packaging/etc/systemd/system/do-agent.service
+  '';
+
+  meta = with lib; {
+    description = "DigitalOcean droplet system metrics agent";
+    longDescription = ''
+      do-agent is a program provided by DigitalOcean that collects system
+      metrics from a DigitalOcean Droplet (on which the program runs) and sends
+      them to DigitalOcean to provide resource usage graphs and alerting.
+    '';
+    homepage = "https://github.com/digitalocean/do-agent";
+    license = licenses.asl20;
+    maintainers = with maintainers; [ yvt ];
+    platforms = platforms.linux;
+  };
+}