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

Change-Id: Ida6f840b6d6b28512cdfac841d51ac2fc94fdb6f
Addresses: blueprint fauxhai-Cleanup
Merge "Cleanup node['cpu']['total'] work-around for fauxhai"