ss-h1: reset message state for repeated use

This lets one "opportunistic" mode http policy SS be able to be used
multiple times.
diff --git a/lib/secure-streams/protocols/ss-h1.c b/lib/secure-streams/protocols/ss-h1.c
index 8db5a41..87b28c2 100644
--- a/lib/secure-streams/protocols/ss-h1.c
+++ b/lib/secure-streams/protocols/ss-h1.c
@@ -519,6 +519,8 @@
 		//		__func__, wsi->lc.gutag);
 
 		h->wsi = NULL;
+		h->hanging_som = 0;
+		h->subseq = 0;
 
 #if defined(LWS_WITH_SERVER)
 		lws_pt_lock(pt, __func__);
@@ -878,6 +880,7 @@
 		if (h->hanging_som) {
 			h->info.rx(ss_to_userobj(h), NULL, 0, LWSSS_FLAG_EOM);
 			h->hanging_som = 0;
+			h->subseq = 0;
 		}
 
 		wsi->http.writeable_len = h->writeable_len = 0;