Fix a couple of flake8 Python warnings (#13763)

* Tools: fix flake8 error

* platforms: fix flake8 error

This is just guessed.

Tools/uorb_graph/create.py

@@ -366,7 +366,7 @@ class Graph(object):
             try:
                 content = f.read()
             except:
-                print('Failed reading file: %s, skipping content.' % path)
+                print('Failed reading file: %s, skipping content.' % file_name)
                 return