Remove old datetime conversion

I missed committing 3 line deletions which remove the old pandas.apply based datetime conversion approach.

Author: ptomasula

HSP2tools/readWDM.py

@@ -129,9 +129,6 @@ def readWDM(wdmfile, hdffile, compress_output=True):
             records = np.asarray(records)
             offsets = np.asarray(offsets)
             dates, values = _process_groups(iarray, farray, records, offsets, tgroup)
-            series = pd.Series(values, index=dates)
-            index = series.index.to_series()
-            series.index = index.apply(lambda x: datetime.datetime(*bits_to_date(x)))
             dates = np.array(dates)
             dates_converted = date_convert(dates, date_epoch, dt_year, dt_month, dt_day, dt_hour, dt_minute, dt_second)
             series = pd.Series(values, index=dates_converted)