Tests: Fix import scope

test/apps/passwd/passwd-changes.py

@@ -3,7 +3,6 @@
 from mosq_test_helper import *
 import json
 import shutil
-import signal
 
 mosq_test.require_features(["WITH_BROKER", "WITH_TLS"])
 

test/broker/09-plugin-load-basic-auth.py

@@ -3,7 +3,6 @@
 # Test whether a plugin can subscribe to the tick event
 
 from mosq_test_helper import *
-import signal
 
 def write_config1(filename, ports, per_listener_settings, plugver):
     with open(filename, 'w') as f:

test/broker/23-security-password-file-reload.py

@@ -1,7 +1,6 @@
 #!/usr/bin/env python3
 
 from mosq_test_helper import *
-import signal
 
 mosq_test.require_features(["WITH_PLUGINS", "WITH_PLUGIN_PASSWORD_FILE", "WITH_TLS"])
 

test/mosq_test.py

@@ -4,6 +4,7 @@ import errno
 import hashlib
 import os
 import platform
+import signal
 import socket
 import ssl
 import subprocess