gpgparsemail: Die on parse error, printing errno thing.

* tools/gpgparsemail.c (parse_message): Revert the change.
* tools/rfc822parse.c (transition_to_body): Set ERRNO.
(transition_to_header, insert_header): Likewise.

--

In the comment of rfc822parse_* functions, it explicitly explained
setting ERRNO on error.  For parser errors, it may not have
appropriate ERRNO, in such a case, use ENOENT.

Fixes-commit: c13e459ffe
Signed-off-by: NIIBE Yutaka <gniibe@fsij.org>

tools/gpgparsemail.c

@@ -654,7 +654,7 @@ parse_message (FILE *fp)
 
 
       if (rfc822parse_insert (msg, line, length))
-	die ("parser failed");
+	die ("parser failed: %s", strerror (errno));
 
       if (info.hashing)
         {