[PATCH] SG IO engine: remember to set io_u->file in init

It's now mandatory, since it supports multiple files now.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
diff --git a/engines/sg.c b/engines/sg.c
index 877264a..6c997bd 100644
--- a/engines/sg.c
+++ b/engines/sg.c
@@ -285,6 +285,7 @@
 	int ret;
 
 	io_u = __get_io_u(td);
+	io_u->file = &td->files[0];
 	assert(io_u);
 
 	hdr = &io_u->hdr;