Log Message:
update to 0.6.21
changes:
-many fixes
-new option: Generate encrypted backups without revealing the user's
 key id via option --hidden-encrypt-key
-translation updates
-cleanup, doc improvement

pkgsrc changes:
-added option to use gnupg2
-drop py-boto dependency -- if we had a dependency for each possible
 backend, it would be just too much. add a MESSAGE pointing to
 some options and information
-minor cleanup