Improve "idempotency" for nuke option

Author: mgreter

lib/sass_spec/test.rb

@@ -15,13 +15,17 @@ def run_spec_test(test_case, options = {})
         f.write(status)
         f.close
       end
+    elsif (File.file?(test_case.status_path))
+      File.unlink(test_case.status_path)
     end
 
     if error.length > 0
       File.open(test_case.error_path, "w+") do |f|
         f.write(error)
         f.close
       end
+    elsif (File.file?(test_case.error_path))
+      File.unlink(test_case.error_path)
     end
 
     File.open(test_case.expected_path, "w+") do |f|