Need to escape "/" in file path

[toru-takahashi]

$ zeng get article 360001287387
Using config file: /Users/takahashi/.zeng.yaml
Info: Request to https://treasuredata.zendesk.com/api/v2/help_center/en-us/articles/360001287387.json
Error: open a_360001287387/a_360001287387_en-us_Writing Job Results into AWS S3 / Riak CS.html: no such file or directory
Usage:
  zeng get article [ArticleID] [flags]

Flags:
  -h, --help   help for article

Global Flags:
      --config string   config file (default is $HOME/.zeng.yaml)

open a_360001287387/a_360001287387_en-us_Writing Job Results into AWS S3 / Riak CS.html: no such file or directory