Remove Expensive log.Debuf(...) statement in blockstore.AllKeysChan?

[kevina]

This statement is causing a major slowdown in AllKeysChan,

	get := func() (*cid.Cid, bool) {
		...
		log.Debug("blockstore: query got key", c)
		...
	}

due to the fact that the Cid is converted to a string which is very expensive due to the conversion to the Base58 representation. This is done even if the log.Debug does not output anything. See #3376.

The question is what to do about it? The easiest thing would be to just remove it or comment it out with a explanation to why.

The other alternative is to only enable it when Debug mode is activated, but this is not the same as the Debug logging level.

I can't seam to find a way to check what the logging level is, if there was I could just use that.

[whyrusleeping]

@kevina I think its fair to remove that one. Its not really necessary here, and isnt a log statement i've ever found useful in debugging.