prevent buildout to log "Unused options for x: md5sum"

option is used, so this warning is incorrect.

slapos/recipe/cmmi/__init__.py

@@ -290,6 +290,7 @@ class Recipe(object):
                 shutil.rmtree(compile_dir)
             os.mkdir(compile_dir)
             try:
+                self.options.get('md5sum') # so that buildout does not complain "unused option md5sum"
                 opt = self.options.copy()
                 opt['destination'] = compile_dir
                 opt['strip-top-level-dir'] = 'false'