BUG/MINOR: http: fix "set-tos" not working in certain configurations

s->req->prod->conn->addr.to.ss_family contains only useful data if
conn_get_to_addr() is called early. If thats not the case (nothing in the
configuration needs the destination address like logs, transparent, ...)
then "set-tos" doesn't work.

Fix this by checking s->req->prod->conn->addr.from.ss_family instead.
Also fix a minor doc issue about set-tos in http-response.

doc/configuration.txt

@@ -2803,7 +2803,8 @@ http-request { allow | deny | tarpit | auth [realm <realm>] | redirect <rule> |
 
 http-response { allow | deny | add-header <name> <fmt> | set-nice <nice> |
                 set-header <name> <fmt> | set-log-level <level> |
-                set-mark <mark> } [ { if | unless } <condition> ]
+                set-mark <mark> | set-tos <tos> }
+              [ { if | unless } <condition> ]
   Access control for Layer 7 responses
 
   May be used in sections:   defaults | frontend | listen | backend

src/proto_http.c

@@ -3213,7 +3213,7 @@ http_req_get_intercept_rule(struct proxy *px, struct list *rules, struct session
 
 		case HTTP_REQ_ACT_SET_TOS:
 #ifdef IP_TOS
-			if (s->req->prod->conn->addr.to.ss_family == AF_INET)
+			if (s->req->prod->conn->addr.from.ss_family == AF_INET)
 				setsockopt(s->req->prod->conn->t.sock.fd, IPPROTO_IP, IP_TOS, &rule->arg.tos, sizeof(rule->arg.tos));
 #endif
 			break;
@@ -3299,7 +3299,7 @@ http_res_get_intercept_rule(struct proxy *px, struct list *rules, struct session
 
 		case HTTP_RES_ACT_SET_TOS:
 #ifdef IP_TOS
-			if (s->req->prod->conn->addr.to.ss_family == AF_INET)
+			if (s->req->prod->conn->addr.from.ss_family == AF_INET)
 				setsockopt(s->req->prod->conn->t.sock.fd, IPPROTO_IP, IP_TOS, &rule->arg.tos, sizeof(rule->arg.tos));
 #endif
 			break;