make code more readable

Followup for https://github.com/voxpupuli/rspec-puppet-facts/pull/180/files#r1632365945

.rubocop.yml

@@ -7,6 +7,9 @@ inherit_gem:
 Layout/LineLength:
   Enabled: false
 
+Style/IfUnlessModifier:
+  Enabled: false
+
 # To match the gem name
 Naming/FileName:
   Exclude:

lib/rspec-puppet-facts.rb

@@ -259,7 +259,9 @@ def self.common_facts
 
     @common_facts[:mco_version] = MCollective::VERSION if mcollective?
 
-    @common_facts[:augeasversion] = Augeas.open(nil, nil, Augeas::NO_MODL_AUTOLOAD).get('/augeas/version') if augeas?
+    if augeas?
+      @common_facts[:augeasversion] = Augeas.open(nil, nil, Augeas::NO_MODL_AUTOLOAD).get('/augeas/version')
+    end
     @common_facts = stringify_keys(@common_facts) if RSpec.configuration.facterdb_string_keys
 
     @common_facts
@@ -296,7 +298,9 @@ def self.mcollective?
   # @return [Array<Hash>]
   # @api private
   def self.meta_supported_os
-    raise StandardError, 'Unknown operatingsystem support in the metadata file!' unless metadata['operatingsystem_support'].is_a? Array
+    unless metadata['operatingsystem_support'].is_a? Array
+      raise StandardError, 'Unknown operatingsystem support in the metadata file!'
+    end
 
     metadata['operatingsystem_support']
   end
@@ -308,7 +312,9 @@ def self.meta_supported_os
   # @api private
   def self.metadata
     return @metadata if @metadata
-    raise StandardError, "Can't find metadata.json... dunno why" unless File.file? metadata_file
+    unless File.file? metadata_file
+      raise StandardError, "Can't find metadata.json... dunno why"
+    end
 
     content = File.read metadata_file
     @metadata = JSON.parse content