additional logging to help diagnose slow QJM logSync

I've been working on diagnosing an issue with a cluster which is seeing slow logSync calls occasionally to QJM. Adding a few more pieces of logging would help this:

• in the warning messages on the client side leading up to a timeout, include which nodes have responded and which ones are still pending
• on the server side, when we actually call FileChannel.force, log a warning if the sync takes longer than 1 second