SPDY: prevented creation of RST_STREAM in protocol error state.

Previously, the frame wasn't sent anyway (and had a wrong status code).

src/http/ngx_http_spdy.c

diff --git a/src/http/ngx_http_spdy.c b/src/http/ngx_http_spdy.c
index 159d8eb..8de0203 100644
--- a/src/http/ngx_http_spdy.c
+++ b/src/http/ngx_http_spdy.c
@@ -1932,6 +1932,7 @@
                    "spdy state protocol error");
 
     if (sc->stream) {
+        sc->stream->out_closed = 1;
         ngx_http_spdy_close_stream(sc->stream, NGX_HTTP_BAD_REQUEST);
     }