Add plugin failed

[luodongseu]

Makes sure these boxes are checked befor submitting your issue - thank you!

• [] If you encounter any problems using the tool, please check if there has a new version to update(Run weex update [pluginname]@latest).
• [] Check the FAQ, make sure there have not the same issue.

Your development environment

2.0.0-beta.32 (Core 2.0.0-beta.32)

The key error stack message.

Steps to reproduce the problem.(Maybe a dotwe link)

Add plugin locally.
weex pugin add ../weexxx-plugin