media attribute with invalid value not parsed correctly

[zcorpan]

[[
If child has a media attribute, and its value is not a valid media query list, or is a valid media query list that evaluates to false, continue to the next child.
]]
http://www.whatwg.org/specs/web-apps/current-work/multipage/embedded-content.html#update-the-source-set

This should say "If child has a media attribute, and its value does not match the environment, continue to the next child."

In particular, media="all, }" is not a valid media query list but should still evaluate to true.

[yoavweiss]

👍