Update location to sys init scripts

The raw.github.com url returns a redirect and won't work in some automation tools.

```sh:
$ curl -ik https://raw.github.com/hashicorp/serf/master/ops-misc/serf.sysv.init
HTTP/1.1 301 Moved Permanently
Date: Fri, 22 Aug 2014 14:36:46 GMT
Server: Apache
Location: https://raw.githubusercontent.com/hashicorp/serf/master/ops-misc/serf.sysv.init
Content-Length: 0
```