Remove collections_port.h from ordered_group.h

Change-Id: Ib81f475d909f9973c78f83961e477d046e24c30d

include/ceres/ordered_groups.h

@@ -33,7 +33,7 @@
 
 #include <map>
 #include <set>
-#include "ceres/collections_port.h"
+#include "ceres/internal/port.h"
 
 namespace ceres {