block: Rename bdrv_set_locked() to bdrv_lock_medium()

While there, make the locked parameter bool.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
diff --git a/block.h b/block.h
index 396ca0e..4691090 100644
--- a/block.h
+++ b/block.h
@@ -212,7 +212,7 @@
 int bdrv_enable_write_cache(BlockDriverState *bs);
 int bdrv_is_inserted(BlockDriverState *bs);
 int bdrv_media_changed(BlockDriverState *bs);
-void bdrv_set_locked(BlockDriverState *bs, int locked);
+void bdrv_lock_medium(BlockDriverState *bs, bool locked);
 void bdrv_eject(BlockDriverState *bs, int eject_flag);
 void bdrv_get_format(BlockDriverState *bs, char *buf, int buf_size);
 BlockDriverState *bdrv_find(const char *name);