Remove "day" argument from log_match api of PTL

FORUM: http://community.pbspro.org/t/does-ptl-log-match-api-need-day-and-starttime-endtime-arguments-both/1392

Day argument is redundant as log_match also contains starttime and endtime (epoch time) as arguments to search/match pattern.

As starttime and endtime provides day information, log_match can use this info to get log files to search/match accordingly.

After this chage log_match api will be:

def log_match(self, msg=None, id=None, n=50, tail=True, allmatch=False,
              regexp=False, max_attempts=None, interval=None,
              starttime=None, endtime=None, level=logging.INFO,
              existence=True)