Remove custom python override

It turns out the python override is fixing the wrong problem. All module
not found issue comes from the fact that `PATH` is overriden and wrong
python3 binary is being used when a program is called from fusesoc.

The change to `PATH` is caused by the python program wrapper, but in
this case it's not necessary for fusesoc. Simply stopping wrapping
fusesoc is enough to fix the issue.

pkgs/python_ot/default.nix

@@ -59,13 +59,21 @@
       preferWheel = true;
     };
   };
+
+  # Nix wraps python programs which causes PATH to change. We want to keep
+  # PATH in case a program needs to invoke user-defined programs.
+  dontwrap-overlay = final: prev: {
+    fusesoc = prev.fusesoc.overridePythonAttrs {
+      dontWrapPythonPrograms = true;
+    };
+  };
 in
   poetry2nix.mkPoetryEnv {
     projectDir = ./.;
-    python = import ./python.nix {python = python3;};
     overrides = [
       preferwheel-overlay
       buildreqs-overlay
+      dontwrap-overlay
       poetry2nix.defaultPoetryOverrides
     ];
   }