3 of the extended qa tests were broken by #9768. This fixes them:

• maxblocksinflight failed because there was a call to self.log in TestManager, but TestManager doesn't have a log attribute. Fixed by passing the log handler from the MaxBlocksInFlight object to the TestManager object
• pruning failed because the string formatting was broken in the calls to self.log.info. Fixed by fixing the formatting.
• smartfees failed because a helper function was calling self.log, but didn't have a log variable. Fixed by making the log object global in that module (my initial fix was to change all the helper functions to methods, but this is less disruptive).

@MarcoFalke has proposed a fix for maxblocksinflight in #9971 and @sdaftuar has a fix for smartfees in #9970 . Both of those are fine and I'm happy to go with them as alternatives. This PR collects fixes for all three breaks in one place.