Ensure boolean properties munged

The props hash is using symbol keys so the previous behavior was never actually munging and unmunging those boolean values

BEFORE:

ONBOOT=true

AFTER:

ONBOOT=yes

lib/puppet/provider/network_config/redhat.rb

@@ -170,7 +170,7 @@ def self.munge(pairs)
     # For all of the remaining values, blindly toss them into the options hash.
     props[:options] = pairs
 
-    %w[onboot hotplug].each do |bool_property|
+    %i[onboot hotplug].each do |bool_property|
       props[bool_property] = (props[bool_property] == 'yes') if props[bool_property]
     end
 
@@ -214,8 +214,8 @@ def self.format_file(filename, providers)
   def self.unmunge(props)
     pairs = {}
 
-    %w[onboot hotplug].each do |bool_property|
-      if props[bool_property]
+    %i[onboot hotplug].each do |bool_property|
+      unless props[bool_property].nil?
         props[bool_property] = (props[bool_property] == true ? 'yes' : 'no')
       end
     end