D-Bus: Increase introspection buffer size

It was apparently possible to hit the 20000 octet limit in some cases,
so increase the limit to avoid process termination due to insufficient
room for preparing a response to Introspect calls.

Signed-off-by: Jouni Malinen <j@w1.fi>

wpa_supplicant/dbus/dbus_new_introspect.c

@@ -257,7 +257,7 @@ DBusMessage * wpa_dbus_introspect(DBusMessage *message,
 	DBusMessage *reply;
 	struct wpabuf *xml;
 
-	xml = wpabuf_alloc(20000);
+	xml = wpabuf_alloc(30000);
 	if (xml == NULL)
 		return NULL;