This is one of the places where "dead code" should be cleared.  I left the dead line as a reminder of the sequence used in the original function.  Honestly it took two, maybe three, passes at this function to get it proper for simultaneous compactions ... with this being the imm compaction.  The dead code is still a reminder if we find another issue at customer site next week.  Will be cleared by the time this goes to 2.0.  The imm compaction's "flag" is whether or not DBImpl::imm_ is set or not.