Prevent errors when caching is disabled

lib/vagrant-cachier/action/ensure_single_cache_root.rb

@@ -21,7 +21,8 @@ module VagrantPlugins
         end
 
         def cache_scoped_to_machine?
-          @env[:machine].config.cache.scope.to_sym == :machine
+          @env[:machine].config.cache.enabled? &&
+            @env[:machine].config.cache.scope.to_sym == :machine
         end
 
         def ensure_single_cache_root_exists!

lib/vagrant-cachier/provision_ext.rb

@@ -34,6 +34,8 @@ module VagrantPlugins
           end
 
           def configure_cache_buckets
+            return unless @env[:machine].config.cache.enabled?
+
             if @env[:machine].config.cache.auto_detect
               Bucket.auto_detect(@env)
             end