patch 8.1.1075: function reference count wrong in Python code

Problem:    Function reference count wrong in Python code.
Solution:   Use "O" instead of "N" for the arguments. (Ben Jackson,
            closes #4188)
diff --git a/src/if_py_both.h b/src/if_py_both.h
index b27f93e..20affe3 100644
--- a/src/if_py_both.h
+++ b/src/if_py_both.h
@@ -1210,7 +1210,7 @@
     if (!(paths = Vim_GetPaths(self)))
 	return NULL;
 
-    spec = PyObject_CallFunction(py_find_spec, "sNN", fullname, paths, target);
+    spec = PyObject_CallFunction(py_find_spec, "sOO", fullname, paths, target);
 
     Py_DECREF(paths);