Standardize on oslo.log.
Log exception stack traces where appropriate.
Add logging to all files.
Remove '[*]' from log messages.
Log command line arguments at Freezer Agent start
so that errors can be traced to specific invocations.
Leave scheduler module mostly unchanged because it
is doing python logging configuration.
Change-Id: I23de0558409e63978303963d592a4e5ee4dee2b5
00db2b0d95