Btrfs: fix a build warning for an unused label

This issue was detected by the "0-DAY kernel build testing".

fs/btrfs/volumes.c: In function 'btrfs_rm_device':
fs/btrfs/volumes.c:1505:1: warning: label 'error_close' defined but not used [-Wunused-label]

Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 32a4948..0b1b7e2 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -1544,7 +1544,6 @@
 
 error_brelse:
 	brelse(bh);
-error_close:
 	if (bdev)
 		blkdev_put(bdev, FMODE_READ | FMODE_EXCL);
 out: