Fix Gazebo crash in building editor when adding door or window (gazeb…

…osim#2276)

BuildingMaker::DetachFromParent: break loop after DetachAllChildren.
Prevents memory corruption by iterating over attachmentMap while removing elements.

gazebo/gui/building/BuildingMaker.cc

@@ -228,8 +228,10 @@ void BuildingMaker::DetachFromParent(const std::string &_child)
     parentManip.second.erase(std::remove(parentManip.second.begin(),
         parentManip.second.end(), _child), parentManip.second.end());
 
-    if (parentManip.second.empty())
+    if (parentManip.second.empty()) {
       this->DetachAllChildren(parentManip.first);
+      break;
+    }
   }
 }