Merge branch 'lm/squelch-bg-progress'

The controlling tty-based heuristics to squelch progress output did not consider that the process may not be talking to a tty at all (e.g. sending the progress to sideband #2). This is a finishing touch to a topic that is already in 'master'. * lm/squelch-bg-progress: progress: treat "no terminal" as being in the foreground