dm crypt: missing kfree in ctr error path

Insert missing kfree() in crypt_iv_essiv_ctr() error path.

Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
diff --git a/drivers/md/dm-crypt.c b/drivers/md/dm-crypt.c
index ecd9ef0..3fa3b24 100644
--- a/drivers/md/dm-crypt.c
+++ b/drivers/md/dm-crypt.c
@@ -175,6 +175,7 @@
 
 	if (err) {
 		ti->error = "Error calculating hash in ESSIV";
+		kfree(salt);
 		return err;
 	}