rpc_flight_recorder: use argparse

This CLI parser isn't using any of the features of chromite's
commandline, so switch it to standard argparse to avoid the dep.

BUG=chromium:1049711
TEST=CQ passes

Change-Id: I0ef2b3917f91a25fcd594dd27c64cfd250f80a2a
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/autotest/+/2044534
Reviewed-by: Allen Li <ayatane@chromium.org>
Tested-by: Mike Frysinger <vapier@chromium.org>
diff --git a/site_utils/rpc_flight_recorder.py b/site_utils/rpc_flight_recorder.py
index b663a46..d0ff928 100755
--- a/site_utils/rpc_flight_recorder.py
+++ b/site_utils/rpc_flight_recorder.py
@@ -4,6 +4,8 @@
 # found in the LICENSE file.
 
 """Standalone service to monitor AFE servers and report to ts_mon"""
+
+import argparse
 import sys
 import time
 import logging
@@ -18,7 +20,6 @@
 # pylint: disable=unused-import
 from autotest_lib.server import site_host_attributes
 from autotest_lib.site_utils import server_manager_utils
-from chromite.lib import commandline
 from chromite.lib import metrics
 from chromite.lib import ts_mon_config
 
@@ -258,7 +259,7 @@
 
 def get_parser():
     """Returns argparse parser"""
-    parser = commandline.ArgumentParser(description=__doc__)
+    parser = argparse.ArgumentParser(description=__doc__)
 
     parser.add_argument('-a', '--afe', action='append', default=[],
                         help='Autotest FrontEnd server to monitor')