Update chianas drive_manager.py to include check for active network traffic

[rjsears]

In certain circumstances ./drive_manager.py can think there is a remote transfer going when there is not. We need to add in a network check like we do on the sending end so we can somewhat gracefully reset if a remote transfer failed and we still think it is going. This came up when I ran out of drive space!!

[rjsears]

Completed. drive_manager.py now actively checks for network traffic as part of determining if we are running a transfer.