Update redis to version 2.6

- Install from source by default because Ubuntu Precise (12.04) still using redis 2.2
- Remove obsolete 'vm' configuration options
- update hash-max-zipmap-* configuration options to hash-max-ziplist-*
- Switch to runit instead of init by default; it's *better*
- Use runit "default-logger" to log to /var/log/redis
- Do not daemonize when using runit; it doesn't work

Your fork of the Atari chef-redis repo seems to be the best one available for installing redis so I'm sending this pull-request to you. Hope you find the changes useful!

Best,

Pat