fix size calculation in keycheck tool

src/mint-tools/taler-mint-keycheck.c

@@ -120,7 +120,9 @@ denomkeys_iter (void *cls,
   struct GNUNET_HashCode hc;
 
   if (ntohl (dki->issue.purpose.size) !=
-      sizeof (struct TALER_DenominationKeyValidityPS))
+      sizeof (struct TALER_DenominationKeyValidityPS) -
+      offsetof (struct TALER_DenominationKeyValidityPS,
+                purpose))
   {
     fprintf (stderr,
              "Denomination key for `%s' has invalid purpose size\n",

src/mintdb/mintdb_keyio.c

@@ -206,7 +206,7 @@ TALER_MINTDB_denomination_key_write (const char *filename,
     goto cleanup;
   wsize = sizeof (struct TALER_DenominationKeyValidityPS);
   if (GNUNET_SYSERR == (wrote = GNUNET_DISK_file_write (fh,
-                                                        &dki->issue.signature,
+                                                        &dki->issue,
                                                         wsize)))
     goto cleanup;
   if (wrote != wsize)