Cleanup symbols that should be static

Run analysis on symbols not used outside of their current file,
turn them into statics.

Signed-off-by: Jens Axboe <axboe@fb.com>
diff --git a/engines/rbd.c b/engines/rbd.c
index 5a4a3e2..9d64efd 100644
--- a/engines/rbd.c
+++ b/engines/rbd.c
@@ -422,7 +422,7 @@
 	return 0;
 }
 
-struct ioengine_ops ioengine = {
+static struct ioengine_ops ioengine = {
 	.name               = "rbd",
 	.version            = FIO_IOOPS_VERSION,
 	.setup              = fio_rbd_setup,