Drop redundant milliseconds from logging

The current code logs the milliseconds twice:

  2020-09-21 00:24:21,706.706 3484 DEBUG VirtualBMC [-] Get power...

The documentation for the logging module in py3 is quite
unambiguous about %(asctime) providing milliseconds.
The documentation in py2 is unclear on what is supposed
to offer, but in practice it works exactly as py3.

Change-Id: Ibb050c58d5fb949316700d7d2db4c77bd62f5e25

virtualbmc/log.py

@@ -17,7 +17,7 @@ from virtualbmc import config
 
 __all__ = ['get_logger']
 
-DEFAULT_LOG_FORMAT = ('%(asctime)s.%(msecs)03d %(process)d %(levelname)s '
+DEFAULT_LOG_FORMAT = ('%(asctime)s %(process)d %(levelname)s '
                       '%(name)s [-] %(message)s')
 LOGGER = None