fixes several bugs around the storage of switches

Summary:
- fixes the 'Manager has no attribute storage' bug
- switch names are now immutable
- breaking change, storage api is not compatible with 2.0

Test Plan: pass

Reviewers: jeff

Reviewed By: jeff

CC: tail, pedro, gabalafou

Differential Revision: http://phabricator.local.disqus.net/D6926