A full disk disables logging instead of pausing it

When MaxScale attempts to log a message when the disk is full, the logging will be disabled. The way to enable isn't obvious from the error message:

Error, writing to the log-file /var/log/maxscale/maxscale.log failed due to 28, No space left on device. Disabling writing to the log.

Improving the message with the steps to enable the logging would make the problem easier to solve. A better solution might be to treat a full disk differently and continue writing to it after the next log rotation.