message: Fix libdefs for new Flow
  Ref: flowtype/flow-typed#2408
diff: @@ -205,13 +205,11 @@ declare class express$Router extends express$Route {
  id: string
  ) => mixed
  ): void;
  -
  - // Can't use regular callable signature syntax due to https://github.com/facebook/flow/issues/3084
  - $call: (
  + (
  req: http$IncomingMessage,
  res: http$ServerResponse,
  next?: ?express$NextFunction
  - ) => void;
  + ): void;
  }
  /*
  @@ -260,6 +258,12 @@ declare class express$Application extends express$Router mixins events$EventEmit
  res: http$ServerResponse,
  next?: ?express$NextFunction
  ): void;
  + // callable signature is not inherited
  + (
  + req: http$IncomingMessage,
  + res: http$ServerResponse,
  + next?: ?express$NextFunction
  + ): void;
  }
  declare type JsonOptions = {
  