updated for version 7.4.172

Problem:    The blowfish code mentions output feedback, but the code is
            actually doing cipher feedback.
Solution:   Adjust names and comments.

src/memline.c

@@ -4914,7 +4914,7 @@ ml_crypt_prepare(mfp, offset, reading)
 	 * block for the salt. */
 	vim_snprintf((char *)salt, sizeof(salt), "%ld", (long)offset);
 	bf_key_init(key, salt, (int)STRLEN(salt));
-	bf_ofb_init(seed, MF_SEED_LEN);
+	bf_cfb_init(seed, MF_SEED_LEN);
     }
 }