Normalize Gemfile & pin tests to rspec < 2.99

Pin to rspec < 2.99 until rspec-puppet officially supports rspec 3.x.
This is to avoid warnings due to deprecated matchers in the
rspec-puppet gem.

This change is also intended to normalize the Gemfile for all stackforge
puppet modules.  This should facilitate pinning gem versions when
releasing new stable branches, since the same diff can be used for all
repos.

Change-Id: I0354bbbe4b55ff31d373c73a76abf1c39312257e
Partial-Bug: #1326034