Add log level argument to ratelimit_test function

If a log message is rate limited, we only need to know about it if we
are actually interested in that log level. We therefore add an argument
to the ratelimit_test function to set the log level of the message
printed if a message is skipped

Change-Id: I5ccd4a78bf7e972fe8b0e7133cd7e08c1e38835f