Serialize NoDevice block device mappings correctly
Serialize NoDevice block device mappings correctly

Fixes TOOLS-180

jhajek/euca2ools,jhajek/euca2ools,gholms/euca2ools,vasiliykochergin/euca2ools,gholms/euca2ools,nagyistoce/euca2ools,vasiliykochergin/euca2ools,nagyistoce/euca2ools