Switch back to using rabbitmq-plugins from system path, drop Puppet 3…

… conditional (voxpupuli#566)

lib/puppet/provider/rabbitmq_plugin/rabbitmqplugins.rb

@@ -1,21 +1,7 @@
 require File.expand_path(File.join(File.dirname(__FILE__), '..', 'rabbitmqctl'))
 Puppet::Type.type(:rabbitmq_plugin).provide(:rabbitmqplugins, parent: Puppet::Provider::Rabbitmqctl) do
-  if Puppet::PUPPETVERSION.to_f < 3
-    if Facter.value(:osfamily) == 'RedHat'
-      commands rabbitmqplugins: '/usr/lib/rabbitmq/bin/rabbitmq-plugins'
-    else
-      commands rabbitmqplugins: 'rabbitmq-plugins'
-    end
-  else
-    if Facter.value(:osfamily) == 'RedHat'
-      has_command(:rabbitmqplugins, '/usr/lib/rabbitmq/bin/rabbitmq-plugins') do
-        environment HOME: '/tmp'
-      end
-    else
-      has_command(:rabbitmqplugins, 'rabbitmq-plugins') do
-        environment HOME: '/tmp'
-      end
-    end
+  has_command(:rabbitmqplugins, 'rabbitmq-plugins') do
+    environment :HOME => "/tmp"
   end
 
   defaultfor feature: :posix