SW-609: Fix mock import

SAS/ResourceAssignment/ResourceAssignmentService/test/test_ra_service_and_rpc.py

@@ -17,13 +17,8 @@ except ImportError:
     print('Please source qpid profile')
     exit(3)
 
-try:
-    from mock import MagicMock
-    from mock import patch
-except ImportError:
-    print('Cannot run test without python MagicMock')
-    print('Please install MagicMock: pip install mock')
-    exit(3)
+from unittest.mock import MagicMock
+from unittest.mock import patch
 
 connection = None
 broker = None