python-2.7.13-3.build.sh: Use “official” URL

```
$ curl -I http://cairographics.org/
HTTP/1.1 301 Moved Permanently
Date: Mon, 24 Jul 2017 12:38:04 GMT
Server: Apache/2.4.10 (Debian)
Location: https://www.cairographics.org/
Content-Type: text/html; charset=iso-8859-1
```

python-2.7.13-3.build.sh

@@ -136,7 +136,7 @@ plaininstall dbus-python-0.83.2 dbus-python-0.83.2.tar.gz https://dbus.freedeskt
 
 (
 	cd build
-	test -e py2cairo-1.10.0.tar.gz || wget https://cairographics.org/releases/py2cairo-1.10.0.tar.bz2
+	test -e py2cairo-1.10.0.tar.gz || wget https://www.cairographics.org/releases/py2cairo-1.10.0.tar.bz2
 	test -d py2cairo-1.10.0 || tar xf py2cairo-1.10.0.tar.bz2
 	cd py2cairo-1.10.0
 	./waf configure --prefix=$PREFIX