block: remove per-queue plugging

Code has been converted over to the new explicit on-stack plugging,
and delay users have been converted to use the new API for that.
So lets kill off the old plugging along with aops->sync_page().

Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 17497d0..251bed7 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -358,7 +358,7 @@
 static void handle_write_error(struct address_space *mapping,
 				struct page *page, int error)
 {
-	lock_page_nosync(page);
+	lock_page(page);
 	if (page_mapping(page) == mapping)
 		mapping_set_error(mapping, error);
 	unlock_page(page);