Update vendor-prefix-align.js

Fix for a check if node exists in `_getValName`.
It got broken in cd5306.

![tumblr_muqetmv38t1riml7wo1_400](https://f.cloud.github.com/assets/872004/1653779/9b78b118-5b3c-11e3-923e-02743692254a.gif)