btrfs: assignment in write_dev_flush() doesn't need two semi-colons

One is enough.

Signed-off-by: Jesper Juhl <jj@chaosbits.net>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 811d9f9..d24a841 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -2732,7 +2732,7 @@
 	 * one reference for us, and we leave it for the
 	 * caller
 	 */
-	device->flush_bio = NULL;;
+	device->flush_bio = NULL;
 	bio = bio_alloc(GFP_NOFS, 0);
 	if (!bio)
 		return -ENOMEM;