A string of Superliga losses followed by one of D.C. United’s worst showings of the year against Houston left the second half of the season somewhat in doubt. Which D.C. United would show up for MLS’ crucial home stretch? The confused squad that started the season 2-7 and lacked any form of cohesion, or the offensive dynamos that ran roughshod over their MLS opponent en route to a 5-0-1 record preceding the All Star break?…