Don't override ignore_paths set in rake task with default value

Author: rodjek

lib/puppet-lint/tasks/puppet-lint.rb

@@ -65,7 +65,7 @@ def define(args, &task_block)
         end
 
         if PuppetLint.configuration.ignore_paths
-          @ignore_paths = PuppetLint.configuration.ignore_paths
+          @ignore_paths ||= PuppetLint.configuration.ignore_paths
         end
 
         if PuppetLint.configuration.pattern