Fix bug #2004 by demoting a log message.
To quote arma: "So instead of stopping your CBT from screaming, you're just
going to throw it in the closet and hope you can't hear it?"
Yep. The log message can happen because at 95% point on the curve, we can be
way beyond the max timeout we've seen, if the curve has few points and is
shallow.
Also applied Nick's rule of thumb for rewriting some other notice log messages
to read like how you would explain them to a raving lunatic on #tor who was
shouting at you demanding what they meant. Hopefully the changes live up to
that standard.