(#39) This change applies the inverse of the ignore_content
variable to the replace parameter on *.set file resources in the
ipset::set class, preventing unmanaged ipsets from having their set
files emptied each puppet run

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Pull Request (PR) description

Per the ipset::unmanaged section in the readme, unmanaged sets won't be kept if the set options are changed, but the set file is still emptied with each puppet run. It does leave the in-memory set in place, but this is less than ideal as in the event of an unexpected reboot the set could remain empty until the set file is next updated.

This change leaves the set file intact in addition to the in-memory ipset for unmanaged sets. This is more inline with my expectation of how an unmanaged set should behave, but I'm curious what you think.

This Pull Request (PR) fixes the following issues

39

This PR will enable using nested arrays for parameter 'set'.

It's required (e.g.) when grouping networks in Hiera.
```
ip4subnetaclass00: '10.0.1.0/24'
ip4subnetaclass01: '10.0.2.0/24'
ip4subnetsaclass:
- "%{alias('ip4subnetaclass00')}"
- "%{alias('ip4subnetaclass01')}"

ip4subnetcclass00: '192.168.0.0/24'
ip4subnetcclass01: '192.168.1.0/24'
ip4subnetscclass:
- "%{alias('ip4subnetcclass00')}"
- "%{alias('ip4subnetcclass01')}"

ip4subnets:
- "%{alias('ip4subnetsaclass')}"
- "%{alias('ip4subnets_cclass')}"

ipset::sets:
ip4subnets:
set: "%{alias('ip4subnets')}"
type: 'hash:net'
```