libfetch: merge some features from FreeBSD:

- Supports HTTP/1.1 308 redirect.
- SSLv[23] HTTPS connections are forbidden by default.
- TLS client certificate validation thru OpenSSL.
- Fixes for user/password encoding, misc.

lib/fetch/http.errors

@@ -1,5 +1,4 @@
-# $FreeBSD: http.errors,v 1.5 2001/05/23 18:52:02 des Exp $
-# $NetBSD: http.errors,v 1.3 2009/02/05 16:59:45 joerg Exp $
+# $FreeBSD$ revision 241840
 #
 # This list is taken from RFC 2068.
 #
@@ -19,6 +18,7 @@
 304 UNCHANGED	Not Modified
 305 INFO	Use Proxy
 307 MOVED	Temporary Redirect
+308 MOVED	Permanent Redirect
 400 PROTO	Bad Request
 401 AUTH	Unauthorized
 402 AUTH	Payment Required