pyqt*: fixup build to close #18250

I don't know why the builder uses `lndir ${dbus-python} $out`,
but this commit should work around the problem caused by
dbus-python starting to propagate some inputs.

pkgs/development/python-modules/pyqt/4.x.nix

@@ -14,6 +14,7 @@ in mkPythonDerivation {
   configurePhase = ''
     mkdir -p $out
     lndir ${dbus-python} $out
+    rm -rf "$out/nix-support"
 
     export PYTHONPATH=$PYTHONPATH:$out/lib/${python.libPrefix}/site-packages
 

pkgs/development/python-modules/pyqt/5.x.nix

@@ -32,6 +32,7 @@ in mkPythonDerivation {
 
     mkdir -p $out
     lndir ${dbus-python} $out
+    rm -rf "$out/nix-support"
 
     export PYTHONPATH=$PYTHONPATH:$out/lib/${python.libPrefix}/site-packages