Swap Facter[].value with Facter.value()

This commit swaps out the usage of Facter['operatingsystem'].value
  with Facter.value(:operatingsystem) in all neutron providers that
  use the array method on a ruby module style syntax.

  This commit doesn't actually fix anything that is broken just
  implements a specific syntax to keep consistency across Puppet
  OpenStack modules.

  https://review.openstack.org/#/c/243849
  https://review.openstack.org/#/c/243854

Change-Id: I623f92a5071c4e61a614319ece08b9495d83ff59

lib/puppet/provider/neutron_agent_linuxbridge/ini_setting.rb

@@ -4,7 +4,7 @@ Puppet::Type.type(:neutron_agent_linuxbridge).provide(
 ) do
 
   def file_path
-    if Facter['operatingsystem'].value == 'Ubuntu'
+    if Facter.value(:operatingsystem) == 'Ubuntu'
       '/etc/neutron/plugins/ml2/ml2_conf.ini'
     else
       '/etc/neutron/plugins/linuxbridge/linuxbridge_conf.ini'

lib/puppet/provider/neutron_agent_ovs/ini_setting.rb

@@ -4,7 +4,7 @@ Puppet::Type.type(:neutron_agent_ovs).provide(
 ) do
 
   def file_path
-    if Facter['operatingsystem'].value == 'Ubuntu'
+    if Facter.value(:operatingsystem) == 'Ubuntu'
       '/etc/neutron/plugins/ml2/ml2_conf.ini'
     else
       '/etc/neutron/plugins/ml2/openvswitch_agent.ini'