Cleanup node['cpu']['total'] work-around for fauxhai

The fauxhai fix for the cpu stanza has merged and is available in
fauxhai version 2.1.0 so reverting the workaround patch and ensuring
fauxhai 2.1.0 is used.

- Remove the node.set for ['cpu']['total'] in the spec tests
- Adjust the Gemfile to use fauxhai 2.1.0
- Adjust the Gemfile.lock

Change-Id: I75e1837871b9ad6d02c40ab8a9d5b127a685b66f
Addresses: blueprint fauxhai-cleanup