This patch aim to update our specs test in order to work with the new
rspec-puppet release 2.0.0, in the mean time, we update rspec syntax in
order to be prepared for rspec 3.x move.
In details:
* Convert 'should' keyword to 'is_expected.to' (prepare rspec 3.x)
* Upgrade and pin rspec-puppet from 1.0.1 to 2.0.0
Change-Id: I6e85576823fc93ac0b7a7dff06032d71682259ad