client: continue support for multiple connections

Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/fio.h b/fio.h
index e46a1a3..a6ef937 100644
--- a/fio.h
+++ b/fio.h
@@ -652,7 +652,7 @@
 extern int warnings_fatal;
 extern int terse_version;
 extern int is_backend;
-extern int is_client;
+extern int nr_clients;
 
 extern struct thread_data *threads;