add 400 status code for build api

Signed-off-by: allencloud <allen.sun@daocloud.io>
(cherry picked from commit c81a818b568e892a7fe37552aff84fbc3736a3a4)
Signed-off-by: Victor Vieux <victorvieux@gmail.com>

api/swagger.yaml

@@ -4417,6 +4417,10 @@ paths:
       responses:
         200:
           description: "no error"
+        400:
+          description: "Bad parameter"
+          schema:
+            $ref: "#/definitions/ErrorResponse"
         500:
           description: "server error"
           schema: