addContentVersionMetaElement: Don't break when metaTag.getAttribute('http-equiv') returns null. Probably a difference btw. jsdom 0.2 and 0.5.
addContentVersionMetaElement: Don't break when metaTag.getAttribute('http-equiv') returns null. Probably a difference btw. jsdom 0.2 and 0.5.

assetgraph/assetgraph-builder