Updated postContainersCreate to use writeJSON.

api.go

@@ -535,14 +535,7 @@ func postContainersCreate(srv *Server, version float64, w http.ResponseWriter, r
 		out.Warnings = append(out.Warnings, "IPv4 forwarding is disabled.")
 	}
 
-	b, err := json.Marshal(out)
-	if err != nil {
-		return err
-	}
-	w.Header().Set("Content-Type", "application/json")
-	w.WriteHeader(http.StatusCreated)
-	w.Write(b)
-	return nil
+    return writeJSON(w, http.StatusCreated, out)
 }
 
 func postContainersRestart(srv *Server, version float64, w http.ResponseWriter, r *http.Request, vars map[string]string) error {