Fixed for variable access waring in Puppet 4.2

Since Puppet version 4.2, allot of warnings are shown while using the redis module.

`Warning: Variable access via 'redis_port' is deprecated. Use '@redis_port' instead`

This fix this, Puppetlabs recommends to use a @-[prefix](http://docs.puppetlabs.com/guides/templating.html#referencing-variables).

Also removed some not needed trailing white spaces.