Install redis-server from .deb

This will downgrade from `2.4.17` to `2.4.14`.

**Proposed migration:**
The user `redis` will be kept and re-used by the package.
Old redis will be stopped, then the new one installed:
```
puppet agent -t # Will install, try to start (which will fail because port in use)
/etc/init.d/redis stop # Stop old
/etc/init.d/redis-server start # Start new

rm /etc/init.d/redis
rm -f /var/run/redis.pid
rm -f /tmp/redis.swap
rm /var/log/redis.log
rm rm /etc/sysctl.d/redis.conf
```