[giow] (3) <video>: Remove some redundant prose, and change when networkState is updated with respect to 'error' events
Fixing https://www.w3.org/Bugs/Public/show_bug.cgi?id=26133
Affected topics: Video and Audio

git-svn-id: http://svn.whatwg.org/webapps@8726 340c8d12-0b0e-0410-8428-c7bf67bfef74