Bugfix cannot reassign variable fr_service

[jorhett]

My apologies. I changed a variable name in my last PR, causing this:

Evaluation Error: Cannot reassign variable '$fr_service' (file: **modules/freeradius/manifests/params.pp, line: 78, column: 15)

There's also an unrelated error where ldap is looking for the version fact as an top-level (legacy) fact.

Evaluation Error: Unknown variable: '::freeradius_version'. (file: **/modules/freeradius/manifests/module/ldap.pp, line: 77, column: 24)