Upgrade to rspec 3

Upgrade from rspec 2.x.x to rspec 3.x.x and make all the necessary
changes for the new API. Some notable changes are stub syntax is now
allow. be_true and be_false no longer exist either use be true, be false
or be_truthy, be_falsey. expect chained with not_to no longer accepts
arguments so instead adjust the specs to use expect with to. its no
longer exists so replace its with describe blocks.
Merge pull request #649 from opscode/rspec3-update

Upgrade to rspec 3