code_checker: Leverage .gitignore by using git ls-files instead of fi…

…nd to get list of ifles to check

scripts/Tools/code_checker

@@ -88,9 +88,11 @@ def check_code(dir_to_check, num_procs, files):
         os.environ["PYTHONPATH"] = dir_to_check
 
     # Get list of files to check
-    files_to_check = run_cmd_no_fail('find %s -name "*.py"' % dir_to_check).splitlines()
+    files_to_check = run_cmd_no_fail('git ls-files %s' % dir_to_check).splitlines()
     if files:
         files_to_check = [item for item in files_to_check if matches(item, files)]
+    else:
+        files_to_check = [item for item in files_to_check if item.endswith(".py")]
 
     pool = ThreadPool(num_procs)
     results = pool.map(run_pylint, files_to_check)