Improve USB device reset logic

BUG=webrtc:7203
NOTRY=True

Review-Url: https://codereview.webrtc.org/2789533002
Cr-Commit-Position: refs/heads/master@{#17656}
diff --git a/PRESUBMIT.py b/PRESUBMIT.py
index c3f2dee..efa80fa 100755
--- a/PRESUBMIT.py
+++ b/PRESUBMIT.py
@@ -471,6 +471,7 @@
 
   test_directories = [
       Join('webrtc', 'tools', 'py_event_log_analyzer'),
+      Join('webrtc', 'tools'),
       Join('webrtc', 'audio', 'test', 'unittests'),
   ] + [
       root for root, _, files in os.walk(Join('tools-webrtc'))