Line consumed by AdcptAcfgmPd8Parser needs to be put back if not used

[rgov]

mi-instrument/mi/dataset/parser/adcpt_acfgm_dcl_pd8.py

Line 306 in ab3f732

line = self._stream_handle.readline() # READ NEXT LINE

While parsing a data burst, the inner loop consumes a line at a time and tests if it matches the sensor data format. If it does not, the data burst is over, so the new particle is emitted, and the function jumps back to the top o the outer loop to start looking for the next data burst.

However, that line has now been consumed and cannot be read again by the outer loop. If the discarded line is the header of the next data burst, parsing will fail.

In existing logs, the DCL happens to be recording power state messages between data bursts, and these can be safely skipped. However it is fragile to expect this and in the near future these messages will not be present in some logs.