Fix error in template if rsyslog_version fact is not present

Below is the error when rsyslog_version is not present.  I ran into this when unit testing another module that has this one as a fixture and I had not added rsyslog_version to the unit test facts.  I consider this more of a safety precaution.

This is the error when adding the unit tests in this PR while the changes to the templates were stashed

```
     Failure/Error: should contain_file('/etc/rsyslog.conf')
     Puppet::Error:
       Failed to parse template rsyslog/rsyslog.conf.erb:
         Filepath: /Users/treydock/puppet/modules/rsyslog/spec/fixtures/modules/rsyslog/templates/rsyslog.conf.erb
         Line: 38
         Detail: private method `split' called for nil:NilClass
```