reads a logfile and returns a dictionary by date
        showing the count of log entries

def _count_by_date(self, fname, all_dates):
        """
        reads a logfile and returns a dictionary by date
        showing the count of log entries
        """
        if not os.path.isfile(fname):
            return {}
        d_log_sum = {}
        with open(fname, "r") as raw_log:
            for line in raw_log:
                cols = line.split(',')
                dte = cols[0].strip('"')[0:10].replace('-', '')
                all_dates.append(dte)
                if dte in d_log_sum:
                    d_log_sum[dte] += 1
                else:
                    d_log_sum[dte] = 1
        return d_log_sum