[telemetry] Move stale .pyc check from Python import to gclient hook.

tools/remove_stale_pyc_files.py

+#!/usr/bin/env python
+# Copyright 2014 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+import os
+import sys
+
+
+def RemoveAllStalePycFiles(base_dir):
+  """Scan directories for old .pyc files without a .py file and delete them."""
+  for dirname, _, filenames in os.walk(base_dir):
+    if '.svn' in dirname or '.git' in dirname:
+      continue
+    for filename in filenames:
+      root, ext = os.path.splitext(filename)
+      if ext != '.pyc':
+        continue
+
+      pyc_path = os.path.join(dirname, filename)
+      py_path = os.path.join(dirname, root + '.py')
+
+      try:
+        if not os.path.exists(py_path):
+          os.remove(pyc_path)
+      except OSError:
+        # Wrap OS calls in try/except in case another process touched this file.
+        pass
+
+    try:
+      os.removedirs(dirname)
+    except OSError:
+      # Wrap OS calls in try/except in case another process touched this dir.
+      pass
+
+
+if __name__ == '__main__':
+  for path in sys.argv[1:]:
+    RemoveAllStalePycFiles(path)