Fix after rebasing on master

Now Tempesta FW has ability to accept both HTTP1 and
HTTP2 connections on the same port. When we create
new connection we don't know real connection type,
so we should set `sk_fill_write_queue` callback
for all tls connections and just return 0 in this
callback if it is not HTTP2 later.

fw/connection.h

@@ -292,7 +292,7 @@ typedef struct {
  */
 #define tfw_h2_context_unsafe(conn)	((TfwH2Ctx *)(&((TfwH2Conn *)conn)->h2))
 #define tfw_h2_context_safe(conn)	\
-	ttls_hs_done(tfw_tls_context(conn)) ? tfw_h2_context_unsafe(conn) : NULL;
+	ttls_hs_done(tfw_tls_context(conn)) ? tfw_h2_context_unsafe(conn) : NULL
 
 
 /* Callbacks used by l5-l7 protocols to operate on connection level. */

fw/sock_clnt.c

@@ -191,9 +191,14 @@ tfw_sk_fill_write_queue(struct sock *sk, unsigned int mss_now, int ss_action)
 	 * set to TCP_CLOSE, so this function will never be called after it.
          */
 	BUG_ON(!conn);
-	BUG_ON(TFW_CONN_PROTO(conn) != TFW_FSM_H2);
 
-	h2 = tfw_h2_context_safe(conn);
+	/*
+	 * This function can be called both for HTTP1 and HTTP2 connections.
+	 * Moreover this function can be called when HTTP2 connection is
+	 * shutdowned before TLS hadshake was finished.
+	 */
+	h2 = TFW_CONN_PROTO(conn) == TFW_FSM_H2 ?
+		tfw_h2_context_safe(conn) : NULL;
 	if (!h2) {
 		if (ss_action == SS_SHUTDOWN)
 			tcp_shutdown(sk, SEND_SHUTDOWN);
@@ -278,9 +283,8 @@ tfw_sock_clnt_new(struct sock *sk)
 		 * find a simple and better solution.
 		 */
 		sk->sk_write_xmit = tfw_tls_encrypt;
-	}
-	if (TFW_CONN_PROTO(conn) == TFW_FSM_H2)
 		sk->sk_fill_write_queue = tfw_sk_fill_write_queue;
+	}
 
 	/* Activate keepalive timer. */
 	mod_timer(&conn->timer,