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.

Conflicts:
  Gemfile

Change-Id: I65bade1443395ce99e69c4704d3e1d85e851b9bb
Partial-Bug: #1326034
(cherry picked from commit d691bf7e65bb34ef8eb10d1c636f0d6d221aa9dd)