document -S and -nopad options in usage information

apps/enc.c

@@ -283,9 +283,11 @@ bad:
 			BIO_printf(bio_err,"%-14s passphrase is the first line of the file argument\n","-kfile");
 			BIO_printf(bio_err,"%-14s the next argument is the md to use to create a key\n","-md");
 			BIO_printf(bio_err,"%-14s   from a passphrase.  One of md2, md5, sha or sha1\n","");
+			BIO_printf(bio_err,"%-14s salt in hex is the next argument\n","-S");
 			BIO_printf(bio_err,"%-14s key/iv in hex is the next argument\n","-K/-iv");
 			BIO_printf(bio_err,"%-14s print the iv/key (then exit if -P)\n","-[pP]");
 			BIO_printf(bio_err,"%-14s buffer size\n","-bufsize <n>");
+			BIO_printf(bio_err,"%-14s disable standard block padding\n","-nopad");
 #ifndef OPENSSL_NO_ENGINE
 			BIO_printf(bio_err,"%-14s use engine e, possibly a hardware device.\n","-engine e");
 #endif