Prevent provider blowing up on ruby 1.8 agents

To be clear, this is not about restoring ruby 1.8 support.  This module
is now puppet 4 only and will not be able to be used on ruby 1.8
systems.

However, some puppet environments contain a mix of puppet 4 (supported)
and older puppet 3 EL6 agents. We don't want unrelated puppet runs to
fail on those old systems just because this module is in the same
environment.

lib/puppet/provider/package/npm.rb

@@ -1,20 +1,22 @@
 require 'puppet/provider/package'
 
-Puppet::Type.type(:package).provide :npm, parent: Puppet::Provider::Package do
+Puppet::Type.type(:package).provide :npm, :parent => Puppet::Provider::Package do # rubocop:disable Style/HashSyntax
   desc 'npm is the package manager for Node.js. This provider only handles global packages.'
 
-  confine feature: :npm
+  # We don't support using this module on puppet 3/ruby 1.8 systems.
+  # However, some puppet environments contain a mix of puppet 4 (supported) and older puppet 3 EL6 agents.
+  # We don't want puppet runs to fail on those old systems just because this module is in the same environment.
+  # rubocop:disable Style/HashSyntax
+  confine :false   => %r{^1\.8}.match(RUBY_VERSION)
+  confine :feature => :npm
 
   has_feature :versionable, :install_options
 
-  if Puppet::Util::Package.versioncmp(Puppet.version, '3.0') >= 0
-    has_command(:npm, 'npm') do
-      is_optional
-      environment HOME: '/root'
-    end
-  else
-    optional_commands npm: 'npm'
+  has_command(:npm, 'npm') do
+    is_optional
+    environment :HOME => '/root'
   end
+  # rubocop:enable Style/HashSyntax
 
   def self.npmlist
     # Ignore non-zero exit codes as they can be minor, just try and parse JSON