Fix private method called for #<Logger

[g3d]

User logger.info to prevent NoMethodError: private method `puts' called for #<Logger

[g3d]

Can you add any info about what improvement you need in this pull request to merge it?

[troelskn]

Yes, sorry for the lack of response. logger - despite its ill-confounded name - is actually an IO and not a Logger. Or at least, that's how it has been used so far. I agree that it would be more meaningful to take a Logger proper, but to conserve BC, a change should work on both types. I imagine this could be done by modifying def self.logger=. If you'll make the change and rebase on top of master, I'll merge it.