Fix connected/connecting semantics

In case a connection is established, but the stream negotiation has not
completed yet, a user may think that they can start sending data,
but this is not the case.

All of the following quotes originate in RFC6120.

As of Ch. 8:

> After a client and a server (or two servers) have completed stream
> negotiation, either party can send XML stanzas.

As of Ch. 7.3.1:

> The parties to a stream MUST consider resource binding as
> mandatory-to-negotiate.

As of Ch. 6.3.1:

> The parties to a stream MUST consider SASL as mandatory-to-negotiate.

As of Ch. 4.3.5:

> The initiating entity MUST NOT attempt to send XML stanzas to entities
> other than itself (i.e., the client's connected resource or any other
> authenticated resource of the client's account) or the server to which
> it is connected until stream negotiation has been completed.
> Even if the initiating entity does attempt to do so, the receiving
> entity MUST NOT accept such stanzas and MUST close the stream with a
> <not-authorized/> stream error [...]

Signed-off-by: Steffen Jaeckel <jaeckel-floss@eyet-services.de>

src/auth.c

@@ -816,7 +816,7 @@ static void _auth(xmpp_conn_t *conn)
 static void _auth_success(xmpp_conn_t *conn)
 {
     tls_clear_password_cache(conn);
-    conn->authenticated = 1;
+    conn->stream_negotiation_completed = 1;
     /* call connection handler */
     conn->conn_handler(conn, XMPP_CONN_CONNECT, 0, NULL, conn->userdata);
 }