Double timestamp written to csv file for 3hr buoy report

[shaunwbell]

When running ARGOS_service_data_converter.py with buoy_3hr -csv flags, the timestamp/index is being written to the file twice. This is unnecessary and should be removed. I imagine its a simple fix. When its fixed, the web dygraphs plot of current buoy met observations will need to be updated again as its been edited to ignore the extra timestamp