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>

drivers/md/dm-crypt.c

@@ -175,6 +175,7 @@ static int crypt_iv_essiv_ctr(struct crypt_config *cc, struct dm_target *ti,
 
 	if (err) {
 		ti->error = "Error calculating hash in ESSIV";
+		kfree(salt);
 		return err;
 	}