Update download links in packaging files.

Use a secure link to the current mirror site.
Signed-off-by: Mark Harris <mark.hsj@gmail.com>

debian/copyright

 This package was debianized by Christopher L Cheney <ccheney@debian.org> on
 Tue, 31 Oct 2000 15:08:22 -0600.
 
-It was downloaded from http://www.vorbis.com/download_unix.psp
+It was downloaded from https://downloads.xiph.org/releases/vorbis/
 
 Upstream Author: Monty <monty@xiph.org>
 

debian/watch

 version=2
 
-http://downloads.xiph.org/releases/vorbis/libvorbis-(.*)\.tar\.gz	debian uupdate
+https://downloads.xiph.org/releases/vorbis/libvorbis-(.*)\.tar\.gz	debian uupdate

libvorbis.spec.in

@@ -5,9 +5,9 @@ Summary:	The Vorbis General Audio Compression Codec.
 
 Group:		System Environment/Libraries
 License:	BSD
-URL:		http://www.xiph.org/
+URL:		https://xiph.org/
 Vendor:		Xiph.org Foundation <team@xiph.org>
-Source:		http://downloads.xiph.org/releases/vorbis/%{name}-%{version}.tar.gz
+Source:		https://downloads.xiph.org/releases/vorbis/%{name}-%{version}.tar.gz
 BuildRoot:	%{_tmppath}/%{name}-%{version}-root
 
 # We're forced to use an epoch since both Red Hat and Ximian use it in their