Calling date --utc to fix default w/o it

Fix the following issue

*** WARNING - Failed to retrieve stats (1/5):
Traceback (most recent call last):
  File "/usr/local/lib/python2.7/dist-packages/StarCluster-0.94-py2.7.egg/starcluster/balancers/sge/__init__.py", line 572, in get_stats
    return self._get_stats()
  File "/usr/local/lib/python2.7/dist-packages/StarCluster-0.94-py2.7.egg/starcluster/balancers/sge/__init__.py", line 538, in _get_stats
    now = self.get_remote_time()
  File "/usr/local/lib/python2.7/dist-packages/StarCluster-0.94-py2.7.egg/starcluster/balancers/sge/__init__.py", line 517, in get_remote_time
    return datetime.datetime.strptime(str, "%a %b %d %H:%M:%S UTC %Y")
  File "/usr/lib/python2.7/_strptime.py", line 325, in _strptime
    (data_string, format))
ValueError: time data 'Tue Aug 20 14:44:18 EDT 2013' does not match format '%a %b %d %H:%M:%S UTC %Y'