fix minor errors

Author: vmittal-msft

tests/test_port_an.py

@@ -1,5 +1,6 @@
 import time
 import os
+import pytest
 
 from swsscommon import swsscommon
 

tests/test_storm_control.py

@@ -4,6 +4,7 @@
 import time
 import json
 from distutils.version import StrictVersion
+import pytest
 
 class TestStormControl(object):
     def setup_db(self,dvs):