Fix some LOG.debug invocations

LOG.debug("Hello %s" % xyz) should be LOG.debug("Hello %s", xyz).
This allows the logging package to skip creating the
formatted log message if the message is not going to be emitted because
of the current log level.

Change-Id: Ie0c91cd940017fd80d1d84b0e56780a1da980858
Merge "Fix some LOG.debug invocations"