actions, privileged_daemon: Drop some unused global statements

Tests:

- Make a privileged method throw and exception after spewing output to stdout
and stderr. The exception caught on the service daemon contains the expected
stdout and stderr messages.

- Sending SIGTERM to privileged daemon shuts down the daemon.

Signed-off-by: Sunil Mohan Adapa <sunil@medhas.org>

plinth/actions.py

@@ -369,7 +369,6 @@ class JSONEncoder(json.JSONEncoder):
 
 def _setup_thread_storage():
     """Setup collection of stdout/stderr from any process in this thread."""
-    global thread_storage
     thread_storage.stdout = b''
     thread_storage.stderr = b''
 
@@ -380,14 +379,12 @@ def _clear_thread_storage():
     Python documentation is silent on whether thread local storage will be
     cleaned up after a thread terminates.
     """
-    global thread_storage
     thread_storage.stdout = None
     thread_storage.stderr = None
 
 
 def get_return_value_from_exception(exception):
     """Return the value to return from server when an exception is raised."""
-    global thread_storage
     return_value = {
         'result': 'exception',
         'exception': {

plinth/privileged_daemon.py

@@ -260,7 +260,6 @@ def _shutdown_server() -> None:
     This must be run in a thread separate from the server.serve_forever()
     otherwise it will deadlock waiting for the shutdown to complete.
     """
-    global _server
     logger.info('SIGTERM received, shutting down the server.')
     if _server:
         _server.shutdown()