reclient_helper: delete directory synchronously

This is for
https://crrev.com/c/4916355/8/reclient_helper.py#177

Let me use synchronous directory deletion as reclient doesn't produce
many log files.

Change-Id: I44f616c9d825bc6b9dbeea329ca1db00a578a9fb
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/4988347
Auto-Submit: Takuto Ikuta <tikuta@chromium.org>
Reviewed-by: Michael Savigny <msavigny@google.com>
Reviewed-by: Junji Watanabe <jwata@google.com>
Commit-Queue: Takuto Ikuta <tikuta@chromium.org>

reclient_helper.py

@@ -164,25 +164,6 @@ def datetime_now():
     return datetime.datetime.utcnow()
 
 
-_test_only_cleanup_logdir_handles = []
-
-
-def cleanup_logdir(log_dir):
-    # Run deletetion command without waiting
-    if sys.platform.startswith('win'):
-        _test_only_cleanup_logdir_handles.append(
-            subprocess.Popen(["rmdir", "/s/q", log_dir],
-                             stdout=subprocess.DEVNULL,
-                             stderr=subprocess.DEVNULL,
-                             shell=True,
-                             creationflags=subprocess.CREATE_NEW_PROCESS_GROUP))
-    else:
-        _test_only_cleanup_logdir_handles.append(
-            subprocess.Popen(["rm", "-rf", log_dir],
-                             stdout=subprocess.DEVNULL,
-                             stderr=subprocess.DEVNULL))
-
-
 def set_reproxy_path_flags(out_dir, make_dirs=True):
     """Helper to setup the logs and cache directories for reclient.
 
@@ -240,7 +221,8 @@ def set_reproxy_path_flags(out_dir, make_dirs=True):
     if len(old_log_dirs) > 5:
         old_log_dirs.sort(key=lambda dir: dir.split("_"), reverse=True)
         for d in old_log_dirs[5:]:
-            cleanup_logdir(os.path.join(log_dir, d))
+            shutil.rmtree(os.path.join(log_dir, d))
+
     os.environ.setdefault("RBE_output_dir", run_log_dir)
     os.environ.setdefault("RBE_proxy_log_dir", run_log_dir)
     os.environ.setdefault("RBE_log_dir", run_log_dir)