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/development/tools/misc/travis/shell.nix

@@ -0,0 +1,11 @@
+# Env to update Gemfile.lock / gemset.nix
+
+with import <nixpkgs> {};
+stdenv.mkDerivation {
+  name = "env";
+  buildInputs = [
+    ruby.devEnv
+    gnumake
+    bundix
+  ];
+}