LibCTDB : initialize ctdb->pnn to -1 when we create a new context

but before we learn the pnn of the local node

(This used to be ctdb commit 2cc48be3219b887b85649a14db311af0549041cf)

ctdb/libctdb/ctdb.c

@@ -151,6 +151,7 @@ struct ctdb_connection *ctdb_connect(const char *addr,
 		log_fn(log_priv, LOG_ERR, "ctdb_connect: no memory", ap);
 		goto fail;
 	}
+	ctdb->pnn = -1;
 	ctdb->outq = NULL;
 	ctdb->doneq = NULL;
 	ctdb->in = NULL;