Ignore late RST, WINDOW_UPDATE.
Ignore late RST, WINDOW_UPDATE.

This commit addresses #639 by ignoring RST and WINDOW_UPDATE
frames on a closed (or-implictly-closed) stream.

creichert/wai,yesodweb/wai,sordina/wai,sordina/wai,creichert/wai,kazu-yamamoto/wai,yesodweb/wai,kazu-yamamoto/wai,sordina/wai,sordina/wai