block: Pass driver-specific options to .bdrv_refresh_filename()

In order to decide whether a blkdebug: filename can be produced or a
json: one is necessary, blkdebug checked whether bs->options had more
options than just "config", "x-image" or "image" (the latter including
nested options). That doesn't work well when generic block layer options
are present.

This patch passes an option QDict to the driver that contains only
driver-specific options, i.e. the options for the general block layer as
well as child nodes are already filtered out. Works much better this
way.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Alberto Garcia <berto@igalia.com>
diff --git a/block/nbd.c b/block/nbd.c
index cd6a587..416f42b 100644
--- a/block/nbd.c
+++ b/block/nbd.c
@@ -342,13 +342,13 @@
     nbd_client_attach_aio_context(bs, new_context);
 }
 
-static void nbd_refresh_filename(BlockDriverState *bs)
+static void nbd_refresh_filename(BlockDriverState *bs, QDict *options)
 {
     QDict *opts = qdict_new();
-    const char *path   = qdict_get_try_str(bs->options, "path");
-    const char *host   = qdict_get_try_str(bs->options, "host");
-    const char *port   = qdict_get_try_str(bs->options, "port");
-    const char *export = qdict_get_try_str(bs->options, "export");
+    const char *path   = qdict_get_try_str(options, "path");
+    const char *host   = qdict_get_try_str(options, "host");
+    const char *port   = qdict_get_try_str(options, "port");
+    const char *export = qdict_get_try_str(options, "export");
 
     qdict_put_obj(opts, "driver", QOBJECT(qstring_from_str("nbd")));