Fix Scenario for MSC handling

Create a buffer for each received message.
There are unclear issues with the use of .raw with ctypes String
buffers.

asn1_value_editor/Scenario.py

@@ -185,11 +185,10 @@ class PollerThread(QThread):
             print 'Failed to open message queue ' + self.q_name
             return -1
         buffer_size = GetMsgQueueBufferSize(msg_q)
-        #p_data_from_mq = DV.new_byte_SWIG_PTR(buffer_size)
-        p_data_from_mq = ctypes.create_string_buffer(buffer_size).raw
         while True:
             if self.stop_requested:
                 return 0
+            p_data_from_mq = ctypes.create_string_buffer(buffer_size).raw
             msg_received_type = RetrieveMessageFromQueue(msg_q,
                                                          buffer_size,
                                                          p_data_from_mq)