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/maddy.nix

@@ -0,0 +1,58 @@
+import ./make-test-python.nix ({ pkgs, ... }: {
+  name = "maddy";
+  meta = with pkgs.lib.maintainers; { maintainers = [ onny ]; };
+
+  nodes = {
+    server = { ... }: {
+      services.maddy = {
+        enable = true;
+        hostname = "server";
+        primaryDomain = "server";
+        openFirewall = true;
+      };
+    };
+
+    client = { ... }: {
+      environment.systemPackages = [
+        (pkgs.writers.writePython3Bin "send-testmail" { } ''
+          import smtplib
+          from email.mime.text import MIMEText
+
+          msg = MIMEText("Hello World")
+          msg['Subject'] = 'Test'
+          msg['From'] = "postmaster@server"
+          msg['To'] = "postmaster@server"
+          with smtplib.SMTP('server', 587) as smtp:
+              smtp.login('postmaster@server', 'test')
+              smtp.sendmail('postmaster@server', 'postmaster@server', msg.as_string())
+        '')
+        (pkgs.writers.writePython3Bin "test-imap" { } ''
+          import imaplib
+
+          with imaplib.IMAP4('server') as imap:
+              imap.login('postmaster@server', 'test')
+              imap.select()
+              status, refs = imap.search(None, 'ALL')
+              assert status == 'OK'
+              assert len(refs) == 1
+              status, msg = imap.fetch(refs[0], 'BODY[TEXT]')
+              assert status == 'OK'
+              assert msg[0][1].strip() == b"Hello World"
+        '')
+      ];
+    };
+  };
+
+  testScript = ''
+    start_all()
+    server.wait_for_unit("maddy.service")
+    server.wait_for_open_port(143)
+    server.wait_for_open_port(587)
+
+    server.succeed("echo test | maddyctl creds create postmaster@server")
+    server.succeed("maddyctl imap-acct create postmaster@server")
+
+    client.succeed("send-testmail")
+    client.succeed("test-imap")
+  '';
+})