server messages BUGFIX session-id in rpc-error can be 0
diff --git a/src/messages_p.h b/src/messages_p.h
index ea7961c..7a2d6d0 100644
--- a/src/messages_p.h
+++ b/src/messages_p.h
@@ -34,7 +34,7 @@
     const char *message_lang;
 
     /* <error-info> */
-    uint32_t sid;
+    int64_t sid;    /* -1 for not set */
     const char **attr;
     uint16_t attr_count;
     const char **elem;